25 results on '"Shaul Yogev"'
Search Results
2. Polarized secretion of Drosophila EGFR ligand from photoreceptor neurons is controlled by ER localization of the ligand-processing machinery.
- Author
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Shaul Yogev, Eyal D Schejter, and Ben-Zion Shilo
- Subjects
Biology (General) ,QH301-705.5 - Abstract
The release of signaling molecules from neurons must be regulated, to accommodate their highly polarized structure. In the developing Drosophila visual system, photoreceptor neurons secrete the epidermal growth factor receptor ligand Spitz (Spi) from their cell bodies, as well as from their axonal termini. Here we show that subcellular localization of Rhomboid proteases, which process Spi, determines the site of Spi release from neurons. Endoplasmic reticulum (ER) localization of Rhomboid 3 is essential for its ability to promote Spi secretion from axons, but not from cell bodies. We demonstrate that the ER extends throughout photoreceptor axons, and show that this feature facilitates the trafficking of the Spi precursor, the ligand chaperone Star, and Rhomboid 3 to axonal termini. Following this trafficking step, secretion from the axons is regulated in a manner similar to secretion from cell bodies. These findings uncover a role for the ER in trafficking proteins from the neuronal cell body to axon terminus.
- Published
- 2010
- Full Text
- View/download PDF
3. The Caenorhabditis elegans anchor cell transcriptome: ribosome biogenesis drives cell invasion through basement membrane
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Daniel S. Costa, Isabel W. Kenny-Ganzert, Qiuyi Chi, Kieop Park, Laura C. Kelley, Aastha Garde, David Q. Matus, Junhyun Park, Shaul Yogev, Bob Goldstein, Theresa V. Gibney, Ariel M. Pani, and David R. Sherwood
- Subjects
Molecular Biology ,Developmental Biology - Abstract
Cell invasion through basement membrane (BM) barriers is important in development, immune function and cancer progression. As invasion through BM is often stochastic, capturing gene expression profiles of actively invading cells in vivo remains elusive. Using the stereotyped timing of Caenorhabditis elegans anchor cell (AC) invasion, we generated an AC transcriptome during BM breaching. Through a focused RNAi screen of transcriptionally enriched genes, we identified new invasion regulators, including translationally controlled tumor protein (TCTP). We also discovered gene enrichment of ribosomal proteins. AC-specific RNAi, endogenous ribosome labeling and ribosome biogenesis analysis revealed that a burst of ribosome production occurs shortly after AC specification, which drives the translation of proteins mediating BM removal. Ribosomes also enrich near the AC endoplasmic reticulum (ER) Sec61 translocon and the endomembrane system expands before invasion. We show that AC invasion is sensitive to ER stress, indicating a heightened requirement for translation of ER-trafficked proteins. These studies reveal key roles for ribosome biogenesis and endomembrane expansion in cell invasion through BM and establish the AC transcriptome as a resource to identify mechanisms underlying BM transmigration.
- Published
- 2023
4. End Binding protein 1 promotes specific motor-cargo association in the cell body prior to axonal delivery of Dense Core Vesicles
- Author
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Junhyun Park, Kenneth G. Miller, Pietro De Camilli, and Shaul Yogev
- Abstract
Axonal transport is key to neuronal function. Efficient transport requires specific motor-cargo association in the soma, yet the mechanisms regulating this early step remain poorly understood. We found that EBP-1, theC. elegansortholog of the canonical microtubule end binding protein EB1, promotes the specific association between kinesin-3/KIF1A/UNC-104 and Dense Core Vesicles (DCVs) prior to their axonal delivery. Using single-neuron,in vivolabelling of endogenous cargo and EBs, we observed reduced axonal abundance and reduced secretion of DCV cargo, but not other KIF1A/UNC-104 cargo, inebp-1mutants. This reduction could be traced back to fewer exit events from the cell body, where EBP-1 colocalized with the DCV sorting machinery at the trans Golgi, suggesting that this is the site of EBP-1 function. In addition to its microtubule binding CH domain, mammalian EB1 interacted with mammalian KIF1A in an EBH domain dependent manner, and expression of mammalian EB1 or the EBH domain was sufficient to rescue DCV transport inebp-1mutants. Our results suggest a model in which kinesin-3 binding and microtubule binding by EBP-1 cooperate to transiently enrich the motor near sites of DCV biogenesis to promote motor-cargo association. In support of this model, tethering either EBP-1 or a kinesin-3 KIF1A/UNC-104 interacting domain from an unrelated protein to the Golgi restored the axonal abundance of DCV proteins inebp-1mutants. These results uncover an unexpected role for a microtubule associated protein and provide insight into how specific kinesin-3 cargo are delivered to the axon.
- Published
- 2023
5. TheC. elegansAnchor Cell Transcriptome: Ribosome Biogenesis Drives Cell Invasion through Basement Membrane
- Author
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Daniel S. Costa, Isabel W. Kenny-Ganzert, Qiuyi Chi, Kieop Park, Laura C. Kelley, Aastha Garde, David Q. Matus, Junhyun Park, Shaul Yogev, Bob Goldstein, Theresa V. Gibney, Ariel M. Pani, and David R. Sherwood
- Abstract
Cell invasion through basement membrane (BM) barriers is important in development, immune function, and cancer progression. As invasion through BM is often stochastic, capturing gene expression profiles of cells actively transmigrating BMin vivoremains elusive. Using the stereotyped timing ofC. elegansanchor cell (AC) invasion, we generated an AC transcriptome during BM breaching. Through a focused RNAi screen of transcriptionally enriched genes, we identified new invasion regulators, including TCTP (Translationally Controlled Tumor Protein). We also discovered gene enrichment of ribosomal proteins. AC-specific RNAi, endogenous ribosome labeling, and ribosome biogenesis analysis revealed a burst of ribosome production occurs shortly after AC specification, which drives the translation of proteins mediating BM removal. Ribosomes also strongly localize to the AC’s endoplasmic reticulum (ER) and the endomembrane system expands prior to invasion. We show that AC invasion is sensitive to ER stress, indicating a heightened requirement for translation of ER trafficked proteins. These studies reveal key roles for ribosome biogenesis and endomembrane expansion in cell invasion through BM and establish the AC transcriptome as a resource to identify mechanisms underlying BM transmigration.
- Published
- 2022
6. Scaled-expansion of the membrane associated cytoskeleton requires conserved kinesin adaptors
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Oliver Glomb, Grace Swaim, Pablo Munoz LLancao, Christopher Lovejoy, Sabyasachi Sutradhar, Junhyun Park, Youjun Wu, Marc Hammarlund, Jonathon Howard, Shawn M. Ferguson, and Shaul Yogev
- Abstract
A periodic lattice of actin rings and spectrin tetramers scaffolds the axonal membrane. How spectrin is delivered to this structure to scale its size to that of the growing axon is unknown. We found that endogenous spectrin, visualized with singe axon resolution in vivo, is delivered to hotspots in the lattice that support its expansion at rates set by axon stretch-growth. Unlike other cytoskeletal proteins, whose apparent slow movement consists of intermittent bouts of fast movements, spectrin moves slowly and processively. We identified a pair of coiled coil proteins that mediate this slow movement and the expansion of the lattice by linking spectrin to kinesin-1. Thus, processive slow transport and local lattice incorporation support scaled cytoskeletal expansion during axon stretch-growth.One-Sentence SummaryKinesin adaptors control spectrin transport and expansion of the membrane periodic skeleton.
- Published
- 2022
7. Neurexin and Frizzled Intercept Axonal-Transport at Microtubule Minus-Ends to Control Synapse Formation
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Santiago Balseiro-Gómez, Junhyun Park, Yang Yue, Chen Ding, Lin Shao, Selim Ҫetinkaya, Caroline Kuzoian, Marc Hammarlund, Kristen J Verhey, and Shaul Yogev
- Subjects
Frizzled ,integumentary system ,Hyperactivation ,Microtubule ,Chemistry ,Mutant ,Neurexin ,Axoplasmic transport ,Kinesin ,Transmembrane protein ,Cell biology - Abstract
Precise synaptic connectivity defines neuronal circuits. Synapse formation is locally determined by transmembrane proteins, yet synaptic material is synthesized remotely and undergoes processive transport in axons. How local synaptogenic signals intercept synaptic cargo in transport to promote its delivery and synapse formation is unknown. We found that control of synaptic cargo delivery at microtubule (MT) minus-ends mediates pro- and anti-synaptogenic activities of presynaptic Neurexin and Frizzled in C. elegans, and identified the atypical kinesin VAB-8/KIF26 as a key molecule in this process. VAB-8/KIF26 levels at synaptic MT minus-ends are controlled by Frizzled and Neurexin, its loss mimics neurexin mutants or Frizzled hyperactivation, and its overexpression can rescue synapse-loss in these backgrounds. VAB-8/KIF26 is required for the synaptic localization of other minus-end proteins and promotes pausing of retrograde transport to allow delivery to synapses. Consistently, reducing retrograde transport rescues synapse-loss in vab-8 and neurexin mutants. These results uncover an important mechanistic link between synaptogenic signaling and axonal transport.
- Published
- 2022
8. Neurexin and frizzled intercept axonal transport at microtubule minus ends to control synapse formation
- Author
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Santiago Balseiro-Gómez, Junhyun Park, Yang Yue, Chen Ding, Lin Shao, Selim Ҫetinkaya, Caroline Kuzoian, Marc Hammarlund, Kristen J. Verhey, and Shaul Yogev
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Synapses ,Animals ,Cell Biology ,Caenorhabditis elegans ,Molecular Biology ,Axonal Transport ,Microtubules ,General Biochemistry, Genetics and Molecular Biology ,Axons ,Developmental Biology - Abstract
Synapse formation is locally determined by transmembrane proteins, yet synaptic material is synthesized remotely and undergoes processive transport in axons. How local synaptogenic signals intercept synaptic cargo in transport to promote its delivery and synapse formation is unknown. We found that the control of synaptic cargo delivery at microtubule (MT) minus ends mediates pro- and anti-synaptogenic activities of presynaptic neurexin and frizzled in C. elegans and identified the atypical kinesin VAB-8/KIF26 as a key molecule in this process. VAB-8/KIF26 levels at synaptic MT minus ends are controlled by frizzled and neurexin; loss of VAB-8 mimics neurexin mutants or frizzled hyperactivation, and its overexpression can rescue synapse loss in these backgrounds. VAB-8/KIF26 is required for the synaptic localization of other minus-end proteins and promotes the pausing of retrograde transport to allow delivery to synapses. Consistently, reducing retrograde transport rescues synapse loss in vab-8 and neurexin mutants. These results uncover a mechanistic link between synaptogenic signaling and axonal transport.
- Published
- 2021
9. Neurexin and Frizzled Signaling Intercept Axonal-Transport at Microtubule Minus-Ends to Control Synapse Formation
- Author
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Santiago Balseiro-Gómez, Yang Yue, Lin Shao, Selim Ҫetinkaya, Caroline Kuzoian, Kristen Verhey, and Shaul Yogev
- Published
- 2021
10. Distinguishing synaptic vesicle precursor navigation of microtubule ends with a single rate constant model
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M. Parkes, M.W. Gramlich, S. Balseiro-Gómez, Shaul Yogev, and S. M. Ali Tabei
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0301 basic medicine ,Science ,Models, Neurological ,Biophysics ,Endosomes ,Synaptic vesicle ,Microtubules ,Article ,03 medical and health sciences ,0302 clinical medicine ,Microtubule ,Animals ,Caenorhabditis elegans ,Cytoskeleton ,Multidisciplinary ,Chemistry ,Microtubule cytoskeleton ,Vesicle ,030104 developmental biology ,Medicine ,Synaptic Vesicles ,Biological physics ,030217 neurology & neurosurgery - Abstract
Axonal motor driven cargo utilizes the microtubule cytoskeleton in order to direct cargo, such as synaptic vesicle precursors (SVP), to where they are needed. This transport requires vesicles to travel up to microns in distance. It has recently been observed that finite microtubule lengths can act as roadblocks inhibiting SVP and increasing the time required for transport. SVPs reach the end of a microtubule and pause until they can navigate to a neighboring microtubule in order to continue transport. The mechanism(s) by which axonal SVPs navigate the end of a microtubule in order to continue mobility is unknown. In this manuscript we model experimentally observed vesicle pausing at microtubule ends in C. elegans. We show that a single rate-constant model reproduces the time SVPs pause at MT-ends. This model is based on the time an SVP must detach from its current microtubule and re-attach to a neighboring microtubule. We show that vesicle pause times are different for anterograde and retrograde motion, suggesting that vesicles utilize different proteins at plus and minus end sites. Last, we show that vesicles do not likely utilize a tug-of-war like mechanism and reverse direction in order to navigate microtubule ends.
- Published
- 2020
11. Vesicle Navigation of Microtubule Ends Distinguished by A Single Rate-Constant Model
- Author
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Santiago Balseiro Gómez, M.W. Gramlich, Mason Parkes, Shaul Yogev, and S. M. Ali Tabei
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Chemistry ,Microtubule ,Vesicle ,Microtubule cytoskeleton ,Biophysics - Abstract
Axonal motor driven cargo utilizes the microtubule cytoskeleton in order to direct cargo, such as presynaptic vesicle precursors, to where they are needed. This transport requires vesicles to travel up to microns in distance. It has recently been observed that finite microtubule lengths can act as roadblocks inhibiting vesicles and increasing the time required for transport. Vesicles reach the end of a microtubule and pause until they can navigate to a neighboring microtubule in order to continue transport. The mechanism by which axonal vesicles navigate the end of a microtubule in order to continue mobility is unknown. In this manuscript we model experimentally observed vesicle pausing at microtubule ends in C. elegans. We show that a single rate-constant model reproduces the time vesicles pause at MT-ends. This model is based on the time a vesicle must detach from its current microtubule and re-attach to a neighboring microtubule. We show that vesicle pause times are different for anterograde and retrograde motion, suggesting that vesicles utilize different proteins at plus and minus end sites. Last, we show that vesicles do not likely utilize a tug-of-war like mechanism and reverse direction in order to navigate microtubule ends.
- Published
- 2020
12. Establishing Neuronal Polarity with Environmental and Intrinsic Mechanisms
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Kang Shen and Shaul Yogev
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Feedback, Physiological ,Neurons ,0301 basic medicine ,General Neuroscience ,Cell Polarity ,Environment ,Biology ,Membrane composition ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,nervous system ,medicine ,Animals ,Humans ,Neuron ,Axon ,Neuronal polarity ,Cytoskeleton ,Neuroscience ,Signal Transduction - Abstract
Neurons are among the most morphologically complex cells. A distinction between two compartments, axon and dendrite, generates cellular domains that differ in membrane composition and cytoskeletal structure, and sets the platform on which morphogens, transcription programs, and synaptic activity sculpt neuronal form. The establishment of this distinction, called Neuronal Polarity, entails interpreting spatial and intrinsic cues and converting them to cytoskeletal rearrangements that give rise to axons and dendrites. Hence, this early developmental event underpins the future functional properties of the neuron to receive and transmit information. Here we review the current understanding of developmental cues and cell biological mechanisms that establish polarity in newborn neurons, synthesizing information from vertebrate and invertebrate model systems.
- Published
- 2017
13. Decision letter: Patronin governs minus-end-out orientation of dendritic microtubules to promote dendrite pruning in Drosophila
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Shaul Yogev
- Subjects
Physics ,biology ,Microtubule ,Biophysics ,Dendrite (mathematics) ,Drosophila (subgenus) ,Orientation (graph theory) ,biology.organism_classification ,Pruning (morphology) - Published
- 2018
14. InterSEPTIN' Kinesins in Dendrites
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Santiago Balseiro Gómez and Shaul Yogev
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0301 basic medicine ,Neurons ,Developmental cell ,Motility ,Kinesins ,Cell Biology ,macromolecular substances ,Dendrites ,Biology ,Microtubules ,General Biochemistry, Genetics and Molecular Biology ,Axons ,Article ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,book.journal ,Kinesin ,Neuronal polarity ,Molecular Biology ,book ,Function (biology) ,Developmental Biology - Abstract
Neuronal function requires axon-dendrite membrane polarity, which depends on sorting of membrane traffic during entry into axons. Due to a microtubule network of mixed polarity, dendrites receive vesicles from the cell body without apparent capacity for directional sorting. We found that, during entry into dendrites, axonally destined cargos move with a retrograde bias toward the cell body, while dendritically destined cargos are biased in the anterograde direction. A microtubule-associated septin (SEPT9), which localizes specifically in dendrites, impedes axonal cargo of kinesin-1/KIF5 and boosts kinesin-3/KIF1 motor cargo further into dendrites. In neurons and in vitro single-molecule motility assays, SEPT9 suppresses kinesin-1/KIF5 and enhances kinesin-3/KIF1 in a manner that depends on a lysine-rich loop of the kinesin motor domain. This differential regulation impacts partitioning of neuronal membrane proteins into axons-dendrites. Thus, polarized membrane traffic requires sorting during entry into dendrites by a septin-mediated mechanism that bestows directional bias on microtubules of mixed orientation.
- Published
- 2018
15. Local inhibition of microtubule dynamics by dynein is required for neuronal cargo distribution
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Mark Horowitz, Shaul Yogev, Adam G. Hendricks, Kang Shen, Celine I. Maeder, and Roshni Cooper
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Cytoplasmic Dyneins ,0301 basic medicine ,Science ,Green Fluorescent Proteins ,Dynein ,General Physics and Astronomy ,Dendrite ,macromolecular substances ,Axonal Transport ,Microtubules ,Time-Lapse Imaging ,Article ,General Biochemistry, Genetics and Molecular Biology ,Animals, Genetically Modified ,03 medical and health sciences ,Microtubule ,Chlorocebus aethiops ,medicine ,Animals ,Caenorhabditis elegans ,Caenorhabditis elegans Proteins ,Neurons ,Microscopy, Confocal ,Multidisciplinary ,COS cells ,biology ,Chemistry ,Dendrites ,General Chemistry ,biology.organism_classification ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,COS Cells ,Mutation ,Dynactin ,Axoplasmic transport - Abstract
Abnormal axonal transport is associated with neuronal disease. We identified a role for DHC-1, the C. elegans dynein heavy chain, in maintaining neuronal cargo distribution. Surprisingly, this does not involve dynein's role as a retrograde motor in cargo transport, hinging instead on its ability to inhibit microtubule (MT) dynamics. Neuronal MTs are highly static, yet the mechanisms and functional significance of this property are not well understood. In disease-mimicking dhc-1 alleles, excessive MT growth and collapse occur at the dendrite tip, resulting in the formation of aberrant MT loops. These unstable MTs act as cargo traps, leading to ectopic accumulations of cargo and reduced availability of cargo at normal locations. Our data suggest that an anchored dynein pool interacts with plus-end-out MTs to stabilize MTs and allow efficient retrograde transport. These results identify functional significance for neuronal MT stability and suggest a mechanism for cellular dysfunction in dynein-linked disease., Microtubule dynamics are essential for axonal transport. In C. elegans, the authors show that dynein heavy chain regulates the spatial distribution of dendritic microtubules which ensures correct transport progression.
- Published
- 2017
16. Cellular and Molecular Mechanisms of Synaptic Specificity
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Shaul Yogev and Kang Shen
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Nervous system ,Time Factors ,Cell Adhesion Molecules, Neuronal ,Growth Cones ,Neurotransmission ,Biology ,Synaptic Transmission ,Retina ,Synapse ,Postsynaptic potential ,Cell Adhesion ,medicine ,Animals ,Humans ,Caenorhabditis elegans ,Eye Proteins ,Growth cone ,Brain function ,Neurons ,Membrane Proteins ,Cell Biology ,Anatomy ,Drosophila melanogaster ,medicine.anatomical_structure ,Neuronal circuits ,Synaptic specificity ,Synapses ,Photoreceptor Cells, Invertebrate ,Neuroscience ,Developmental Biology - Abstract
Precise connectivity in neuronal circuits is a prerequisite for proper brain function. The dauntingly complex environment encountered by axons and dendrites, even after navigation to their target area, prompts the question of how specificity of synaptic connections arises during development. We review developmental strategies and molecular mechanisms that are used by neurons to ensure their precise matching of pre- and postsynaptic elements. The emerging theme is that each circuit uses a combination of simple mechanisms to achieve its refined, often complex connectivity pattern. At increasing levels of resolution, from lamina choice to subcellular targeting, similar signaling concepts are reemployed to narrow the choice of potential matches. Temporal control over synapse development and synapse elimination further ensures the specificity of connections in the nervous system.
- Published
- 2014
17. MTQuant: 'Seeing' Beyond the Diffraction Limit in Fluorescence Images to Quantify Neuronal Microtubule Organization
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Mark Horowitz, Shaul Yogev, Roshni Cooper, and Kang Shen
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Diffraction ,Microtubule ,law ,Bundle ,Microscopy ,Axoplasmic transport ,Biology ,Electron microscope ,Biological system ,Fluorescence ,law.invention ,Rendering (computer graphics) - Abstract
Motivation:Microtubules (MTs) are polarized polymers that are critical for cell structure and axonal transport. They form a bundle in neurons, but beyond that, their organization is relatively unstudied.Results:We present MTQuant, a method for quantifying MT organization using light microscopy, which distills three parameters from MT images: the spacing of MT minus-ends, their average length, and the average number of MTs in a cross-section of the bundle. This method allows for robust and rapid in vivo analysis of MTs, rendering it more practical and more widely applicable than commonly-used electron microscopy reconstructions. MTQuant was successfully validated with three ground truth data sets and applied to over 3000 images of MTs in a C. elegans motor neuron.Availability:MATLAB code is available at http://roscoope.github.io/MTQuantContact:horowitz@stanford.eduSupplementary informationSupplementary data are available at Bioinformatics online.
- Published
- 2016
18. Microtubule Organization Determines Axonal Transport Dynamics
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Mark Horowitz, Richard D. Fetter, Kang Shen, Shaul Yogev, and Roshni Cooper
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0301 basic medicine ,Polymers ,Dynein ,Kinesins ,Biology ,Axonal Transport ,Microtubules ,Time-Lapse Imaging ,Article ,03 medical and health sciences ,Microtubule ,Live cell imaging ,medicine ,Animals ,Cytoskeleton ,Caenorhabditis elegans ,Motor Neurons ,Microscopy ,General Neuroscience ,Dynamics (mechanics) ,Dyneins ,Motor neuron ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,Axoplasmic transport ,Kinesin ,Microtubule-Associated Proteins ,Signal Transduction - Abstract
Axonal microtubule (MT) arrays are the major cytoskeleton substrate for cargo transport. How MT organization, i.e., polymer length, number, and minus-end spacing, is regulated and how it impinges on axonal transport are unclear. We describe a method for analyzing neuronal MT organization using light microscopy. This method circumvents the need for electron microscopy reconstructions and is compatible with live imaging of cargo transport and MT dynamics. Examination of a C. elegans motor neuron revealed how age, MT-associated proteins, and signaling pathways control MT length, minus-end spacing, and coverage. In turn, MT organization determines axonal transport progression: cargoes pause at polymer termini, suggesting that switching MT tracks is rate limiting for efficient transport. Cargo run length is set by MT length, and higher MT coverage correlates with shorter pauses. These results uncover the principles and mechanisms of neuronal MT organization and its regulation of axonal cargo transport.
- Published
- 2016
19. Drosophila EGFR signalling is modulated by differential compartmentalization of Rhomboid intramembrane proteases
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Eyal D. Schejter, Ben-Zion Shilo, and Shaul Yogev
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rho GTP-Binding Proteins ,Proteases ,Biology ,Endoplasmic Reticulum ,Article ,General Biochemistry, Genetics and Molecular Biology ,Cell Line ,Animals ,Drosophila Proteins ,Secretion ,Eye Proteins ,Receptors, Invertebrate Peptide ,Receptor ,Molecular Biology ,Secretory pathway ,Epidermal Growth Factor ,General Immunology and Microbiology ,Hydrolysis ,General Neuroscience ,Rhomboid ,Serine Endopeptidases ,Membrane Proteins ,Intracellular Membranes ,Cell Compartmentation ,Cell biology ,ErbB Receptors ,Drosophila melanogaster ,Germ Cells ,Cell culture ,Chaperone (protein) ,biology.protein ,Protein Kinases ,Intracellular ,Signal Transduction - Abstract
We explore the role of differential compartmentalization of Rhomboid (Rho) proteases that process the Drosophila EGF receptor ligands, in modulating the amount of secreted ligand and consequently the level of EGF receptor (EGFR) activation. The mSpitz ligand precursor is retained in the ER, and is trafficked by the chaperone Star to a late compartment of the secretory pathway, where Rho-1 resides. This work demonstrates that two other Rho proteins, Rho-2 and Rho-3, which are expressed in the germ line and in the developing eye, respectively, cleave the Spitz precursor and Star already in the ER, in addition to their activity in the late compartment. This property attenuates EGFR activation, primarily by compromising the amount of chaperone that can productively traffic the ligand precursor to the late compartment, where cleavage and subsequent secretion take place. These observations identify changes in intracellular compartment localization of Rho proteins as a basis for signal attenuation, in tissues where EGFR activation must be highly restricted in space and time.
- Published
- 2008
20. Rhomboid cleaves Star to regulate the levels of secreted Spitz
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Eitan Bibi, Alexandra Wojtalla, Gunter Merdes, Eyal D. Schejter, Shari Carmon, Aderet Reich, Ben-Zion Shilo, Shaul Yogev, and Rachel Tsruya
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endocrine system ,Embryo, Nonmammalian ,animal structures ,Endosome ,Intramembrane protease ,Recombinant Fusion Proteins ,animal diseases ,Green Fluorescent Proteins ,Molecular Sequence Data ,Endosomes ,Transfection ,Article ,General Biochemistry, Genetics and Molecular Biology ,Cell Line ,Animals ,Drosophila Proteins ,Humans ,Amino Acid Sequence ,Molecular Biology ,Late endosome ,Epidermal Growth Factor ,General Immunology and Microbiology ,biology ,General Neuroscience ,Endoplasmic reticulum ,Rhomboid ,Membrane Proteins ,biochemical phenomena, metabolism, and nutrition ,Transmembrane protein ,Transport protein ,ErbB Receptors ,Protein Transport ,Transmembrane domain ,Lac Operon ,Biochemistry ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,biology.protein ,bacteria ,Drosophila ,Protein Binding ,Signal Transduction - Abstract
Intracellular trafficking of the precursor of Spitz (Spi), the major Drosophila EGF receptor (EGFR) ligand, is facilitated by the chaperone Star, a type II transmembrane protein. This study identifies a novel mechanism for modulating the activity of Star, thereby influencing the levels of active Spi ligand produced. We demonstrate that Star can efficiently traffic Spi even when present at sub-stoichiometric levels, and that in Drosophila S(2)R(+) cells, Spi is trafficked from the endoplasmic reticulum to the late endosome compartment, also enriched for Rhomboid, an intramembrane protease. Rhomboid, which cleaves the Spi precursor, is now shown to also cleave Star within its transmembrane domain both in cell culture and in flies, expanding the repertoire of known Rhomboid substrates to include both type I and type II transmembrane proteins. Cleavage of Star restricts the amount of Spi that is trafficked, and may explain the exceptional dosage sensitivity of the Star locus in flies.
- Published
- 2007
21. The Apical Determinants aPKC and dPatj Regulate Frizzled-Dependent Planar Cell Polarity in the Drosophila Eye
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Marek Mlodzik, Shaul Yogev, and Alexandre Djiane
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Frizzled ,Macromolecular Substances ,Down-Regulation ,Plasma protein binding ,Biology ,Eye ,General Biochemistry, Genetics and Molecular Biology ,Receptors, G-Protein-Coupled ,Cell membrane ,Cell polarity ,medicine ,Animals ,Drosophila Proteins ,Phosphorylation ,Eye Proteins ,Protein Kinase C ,Binding Sites ,Tight Junction Proteins ,Polarity (international relations) ,Biochemistry, Genetics and Molecular Biology(all) ,Cell Membrane ,Intracellular Signaling Peptides and Proteins ,Cell Polarity ,Membrane Proteins ,Epithelial Cells ,Anatomy ,biology.organism_classification ,Frizzled Receptors ,Up-Regulation ,respiratory tract diseases ,Cell biology ,Drosophila melanogaster ,medicine.anatomical_structure ,Cytoplasm ,Photoreceptor Cells, Invertebrate ,Drosophila Protein ,Protein Binding - Abstract
SummaryPlanar cell polarity (PCP) is a common feature of many vertebrate and invertebrate epithelia and is perpendicular to their apical/basal (A/B) polarity axis. While apical localization of PCP determinants such as Frizzled (Fz1) is critical for their function, the link between A/B polarity and PCP is poorly understood. Here, we describe a direct molecular link between A/B determinants and Fz1-mediated PCP establishment in the Drosophila eye. We demonstrate that dPatj binds the cytoplasmic tail of Fz1 and propose that it recruits aPKC, which in turn phosphorylates and inhibits Fz1. Accordingly, components of the aPKC complex and dPatj produce PCP defects in the eye. We also show that during PCP signaling, aPKC and dPatj are downregulated, while Bazooka is upregulated, suggesting an antagonistic effect of Bazooka on dPatj/aPKC. We propose a model whereby the dPatj/aPKC complex regulates PCP by inhibiting Fz1 in cells where it should not be active.
- Published
- 2005
22. Sequential activation of ETS proteins provides a sustained transcriptional response to EGFR signaling
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Eyal D. Schejter, Arkadi Shwartz, Shaul Yogev, and Ben-Zion Shilo
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Gene isoform ,MAPK/ERK pathway ,Nerve Tissue Proteins ,Biology ,Phenotype ,Photoreceptor cell ,Cell biology ,DNA-Binding Proteins ,ErbB Receptors ,Imaginal disc ,medicine.anatomical_structure ,Proto-Oncogene Proteins ,Eye development ,medicine ,Animals ,Drosophila Proteins ,Drosophila ,sense organs ,Signal transduction ,Molecular Biology ,Transcription factor ,Developmental Biology ,Signal Transduction ,Transcription Factors - Abstract
How signal transduction, which is dynamic and fluctuating by nature, is converted into a stable trancriptional response, is an unanswered question in developmental biology. Two ETS-domain transcription factors encoded by the pointed (pnt) locus, PntP1 and PntP2, are universal downstream mediators of EGFR-based signaling in Drosophila. Full disruption of pnt function in developing eye imaginal discs reveals a photoreceptor recruitment phenotype, in which only the R8 photoreceptor cell type is specified within ommatidia. Specific disruption of either pntP1 or pntP2 resulted in the same R8-only phenotype, demonstrating that both Pnt isoforms are essential for photoreceptor recruitment. We show that the two Pnt protein forms are activated in a sequential manner within the EGFR signaling pathway: MAPK phosphorylates and activates PntP2, which in turn induces pntP1 transcription. Once expressed, PntP1 is constitutively active and sufficient to induce target genes essential for photoreceptor development. Pulse-chase experiments indicate that PntP1 is stable for several hours in the eye disc. Sequential ETS-protein recruitment therefore allows sustained induction of target genes, beyond the transient activation of EGFR.
- Published
- 2013
23. Versatility of EGF receptor ligand processing in insects
- Author
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Tal Rousso, Shaul Yogev, Ben-Zion Shilo, and Eyal D. Schejter
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Gene isoform ,TGF alpha ,Star ,Insecta ,medicine.medical_treatment ,Cleavage (embryo) ,Endoplasmic Reticulum ,Ligands ,EGF receptor ,Rhomboid ,medicine ,Animals ,Humans ,Protein Isoforms ,Receptor ,Molecular Biology ,Protease ,biology ,Ligand ,Cell Biology ,Cell biology ,ErbB Receptors ,Chaperone (protein) ,biology.protein ,EGF ligand processing ,Developmental Biology ,Molecular Chaperones ,Signal Transduction - Abstract
Processing of EGF-family ligands is an essential step in triggering the EGF receptor pathway, which fulfills a diverse set of roles during development and tissue maintenance. We describe a mechanism of ligand processing which is unique to insects, and possibly to other invertebrates. This mechanism relies on ligand precursor trafficking from the ER by a chaperone, Star (S), and precursor cleavage by Rhomboids, a family of intra-membrane protease. Remarkably, the ability of Rhomboids to cleave S as well, endows the pathway with additional diversity. Rhomboid isoforms which also reside in the ER inactivate the chaperone before any ligand was trafficked, thus significantly reducing the level of ligand that will eventually be processed and secreted. ER localization also serves as a critical feature in trafficking the entire ligand-processing machinery to axonal termini, as the ER extends throughout the axon. Finally, examination of diverse species of insects demonstrates the evolution of chaperone cleavability, indicating that the primordial processing machinery could support long-range signaling by the ligand. Altering the intracellular localization of critical components of a conserved signaling cassette therefore provides an evolutionary mechanism for modulation of signaling levels, and diversification of the biological settings where the pathway functions.
- Published
- 2010
24. Polarized secretion of Drosophila EGFR ligand from photoreceptor neurons is controlled by ER localization of the ligand-processing machinery
- Author
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Eyal D. Schejter, Shaul Yogev, and Ben-Zion Shilo
- Subjects
Cell signaling ,QH301-705.5 ,Cell Biology/Neuronal Signaling Mechanisms ,Recombinant Fusion Proteins ,Axon terminus ,Endosomes ,Biology ,Endoplasmic Reticulum ,Ligands ,Cell Biology/Cell Signaling ,General Biochemistry, Genetics and Molecular Biology ,Developmental Biology/Molecular Development ,Cell Biology/Membranes and Sorting ,Epidermal growth factor ,Cell polarity ,Animals ,Drosophila Proteins ,Protein Isoforms ,Secretion ,Biology (General) ,Epidermal Growth Factor ,General Immunology and Microbiology ,Developmental Biology/Morphogenesis and Cell Biology ,General Neuroscience ,Rhomboid ,Endoplasmic reticulum ,Cell Polarity ,Membrane Proteins ,Cell biology ,Developmental Biology/Neurodevelopment ,ErbB Receptors ,Drosophila melanogaster ,nervous system ,Developmental Biology/Cell Differentiation ,Photoreceptor Cells, Invertebrate ,Signal transduction ,General Agricultural and Biological Sciences ,Research Article ,Signal Transduction - Abstract
Trafficking within the endoplasmic reticulum and specialized localization of the intra-membrane protease Rhomboid regulate EGF ligand-dependent signaling in Drosophila photoreceptor axon termini., The release of signaling molecules from neurons must be regulated, to accommodate their highly polarized structure. In the developing Drosophila visual system, photoreceptor neurons secrete the epidermal growth factor receptor ligand Spitz (Spi) from their cell bodies, as well as from their axonal termini. Here we show that subcellular localization of Rhomboid proteases, which process Spi, determines the site of Spi release from neurons. Endoplasmic reticulum (ER) localization of Rhomboid 3 is essential for its ability to promote Spi secretion from axons, but not from cell bodies. We demonstrate that the ER extends throughout photoreceptor axons, and show that this feature facilitates the trafficking of the Spi precursor, the ligand chaperone Star, and Rhomboid 3 to axonal termini. Following this trafficking step, secretion from the axons is regulated in a manner similar to secretion from cell bodies. These findings uncover a role for the ER in trafficking proteins from the neuronal cell body to axon terminus., Author Summary Cells secrete signaling molecules that trigger a variety of responses in neighboring cells by activating their respective cell-surface receptors. Because many cells in an organism are polarized, regulating the precise location of ligand secretion is important for controlling the position and nature of the response. During the development of the compound eye of the fruit fly Drosophila, for example, a ligand of the epidermal growth factor family called Spitz (Spi) is secreted from both the apical and basal (axonal) poles of photoreceptor cells but with different outcomes. Photoreceptor cells are recruited to the developing eye following apical secretion of Spi. Conversely, basal secretion of this same ligand, at a significant distance from the cell body, triggers differentiation of cells in the outer layer of the brain. Although secretion of Spi is known to occur at both poles of the cell, one important question is how Spi and its processing machinery are trafficked throughout the length of the photoreceptor axon to achieve basal secretion. In this study we show that the key to axonal trafficking is the regulated localization of Spi and its processing machinery, including the intramembrane protease Rhomboid, to sites within the endoplasmic reticulum (ER), which extends along the length of the axon. Two different Rhomboid proteins are expressed in photoreceptor cells, but only one of them is localized to the ER. We show that this ER-localized Rhomboid is indeed necessary and sufficient for Spi processing at axon termini. Our work therefore demonstrates how variations in intracellular localization of conserved signaling components can alter signaling outcomes dramatically. It also highlights the importance of the ER in trafficking proteins along the axon.
- Published
- 2010
25. Generation of distinct signaling modes via diversification of the Egfr ligand-processing cassette
- Author
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Ben-Zion Shilo, Shaul Yogev, Jeremy A. Lynch, Siegfried Roth, Tal Rousso, and Eyal D. Schejter
- Subjects
Proteases ,animal structures ,Intramembrane protease ,Blotting, Western ,Biology ,Bioinformatics ,Cleavage (embryo) ,Endoplasmic Reticulum ,Ligands ,Cell Line ,Gene Duplication ,Gene duplication ,Compartment (development) ,Animals ,Drosophila Proteins ,Molecular Biology ,In Situ Hybridization ,Tribolium ,Endoplasmic reticulum ,Rhomboid ,fungi ,Membrane Proteins ,Cell Biology ,Transforming Growth Factor alpha ,Ligand (biochemistry) ,Subcellular localization ,Immunohistochemistry ,Cell biology ,ErbB Receptors ,Biochemistry ,Chaperone (protein) ,biology.protein ,Drosophila ,Developmental Biology ,Signal Transduction - Abstract
Egfr ligand processing in Drosophila involves trafficking of the ligand precursor by the chaperone Star from the endoplasmic reticulum (ER) to a secretory compartment, where the precursor is cleaved by the intramembrane protease Rhomboid. Some of the Drosophila Rhomboids also reside in the ER, where they attenuate signaling by premature cleavage of Star. The genome of the flour beetle Tribolium castaneum contains a single gene for each of the ligand-processing components, providing an opportunity to assess the regulation and impact of a simplified ligand-processing cassette. We find that the central features of ligand retention, trafficking by the chaperone and cleavage by Rhomboid have been conserved. The single Rhomboid is localized to both ER and secretory compartments. However, we show that Tribolium Star is refractive to Rhomboid cleavage. Consequently, this ligand-processing system effectively mediates long-range Egfr activation in the Tribolium embryonic ventral ectoderm, despite ER localization of Rhomboid. Diversification of the Egfr signaling pathway appears to have coupled gene duplication events with modulation of the biochemical properties and subcellular localization patterns of Rhomboid proteases and their substrates.
- Published
- 2010
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