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Abstract: Carotenoids (CARs) are a group of pigments that perform several important physiological functions in all kingdoms of living organisms. CARs serve as protective agents, which are essential structural components of photosynthetic complexes and membranes, and they play an important role in the light harvesting mechanism of photosynthesizing plants and cyanobacteria. The protection against reactive oxygen species, realized by quenching of singlet oxygen and the excited states of photosensitizing molecules, as well as by the scavenging of free radicals, is one of the main biological functions of CARs. X-ray crystallographic localization of CARs revealed that they are present at functionally and structurally important sites of both the PSI and PSII reaction centers. Characterization of a CAR-less cyanobacterial mutant revealed that while the absence of CARs prevents the formation of PSII complexes, it does not abolish the assembly and function of PSI. CAR molecules assist in the formation of protein subunits of the photosynthetic complexes by gluing together their protein components. In addition to their aforementioned indispensable functions, CARs have a substantial role in the formation and maintenance of proper cellular architecture, and potentially also in the protection of the translational machinery under stress conditions. [Copyright &y& Elsevier]

Influence of the modification of the cyanobacterial light-harvesting complex [i.e. phycobilisomes (PBS)] on the surface electric properties and the functions of photosynthetic membranes was investigated. We used four PBS mutant strains of Synechocystis sp. PCC6803 as follows: PAL (PBS-less), CK (phycocyanin-less), BE (PSII-PBS-less) and PSI-less/ apcE− (PSI-less with detached PBS). Modifications of the PBS content lead to changes in the cell morphology and surface electric properties of the thylakoid membranes as well as in their functions, such as photosynthetic oxygen-evolving activity, P700 kinetics and energy transfer between the pigment-protein complexes. Data reveal that the complete elimination of PBS in the PAL mutant causes a slight decrease in the electric dipole moments of the thylakoid membranes, whereas significant perturbations of the surface charges were registered in the membranes without assembled PBS-PSII macrocomplex (BE mutant) or PSI complex (PSI-less mutant). These observations correlate with the detected alterations in the membrane structural organization. Using a polarographic oxygen rate electrode, we showed that the ratio of the fast to the slow oxygen-evolving PSII centers depends on the partial or complete elimination of light-harvesting complexes, as the slow operating PSII centers dominate in the PBS-less mutant and in the mutant with detached PBS. [ABSTRACT FROM AUTHOR]

Abstract: Glycoglycerolipids are dominant lipids of photosynthetic organisms, i.e. higher plants and cyanobacteria. X-ray crystallographic localization of glycerolipids revealed that they are present at functionally and structurally important sites of both the PS I and PS II reaction centres. Phosphatidylglycerol (PG) is an indispensible member of glycerolipids, including the formation of functionally active oligomers of the reaction centres both PS I and PS II. Lipids assist in the assembly of protein subunits of the photosynthetic machinery by pasting the individual protein components together. PG is needed to glue CP43 to the reaction centre core. PG and digalactosyldiacylglycerol (DGDG) interact in photosynthetic processes: PG alone controls electron transport at the acceptor site of PS II, and together with DGDG is involved in electron transport at the donor site of PS II. PG is crucial for the formation of division rings and is implicated in the fission of cyanobacteria. [Copyright &y& Elsevier]

Abstract: To explore the possible effect of phosphatidylglycerol (PG) on the surface electric properties and chlorophyll fluorescence characteristics we used electric light scattering technique and 77K chlorophyll fluorescence of thylakoid membranes from a cyanobacterium, Synechocystis PCC6803 (wild type) and its pgsA mutant defective in PG synthesis. We found a strong decrease in the permanent and induced electric dipole moments of the mutant thylakoids, following long-term PG depletion parallel with a decrease of the emission peak from PSI and an increase of the emission peak from PSII. Partial recovery of the electric state of thylakoid membranes was observed at re-addition of PG to the mutant cells depleted of PG for 21days. This change in the electric dipole moments is probably due to a decrease in PG content and progressive structural alterations in the macroorganization of the photosynthetic complexes induced by PG deprivation. Our results suggest that the depletion of a lipid, which carries a negative charge, despite its small contribution to the overall lipid content, significantly perturbs the surface charge of the membranes. These changes are related with the chlorophyll fluorescence emission ratios of two photosystems and may partly explain our earlier results concerning the PG requirement for the function and assembly of photosystems I and II reaction centers. [Copyright &y& Elsevier]

Our earlier studies with the pgsA mutant of Synechocystis PCC6803 demonstrated the important role of phosphatidylglycerol (PG) in PSII dimer formation and in electron transport between the primary and secondary electron-accepting plastoquinones of PSII. Using a long-term depletion of PG from pgsA mutant cells, we could induce a decrease not only in PSII but also in PSI activity. Simultaneously with the decrease in PSI activity, dramatic structural changes of the PSI complex were detected. A 21-d PG depletion resulted in the degradation of PSI trimers and concomitant accumulation of monomer PSI. The analyses of PSI particles isolated by MonoQ chromatography showed that, following the 21-d depletion, PSI trimers were no longer detectable in the thylakoid membranes. Immunoblot analyses revealed that the PSI monomers accumulating in the PG-depleted mutant cells do not contain PsaL, the protein subunit thought to be responsible for the trimer formation. Nevertheless, the trimeric structure of PSI reaction center could be restored by readdition of PG, even in the presence of the protein synthesis inhibitor lincomycin, indicating that free PsaL was present in thylakoid membranes following the 21-d PG depletion. Our data suggest an indispensable role for PG in the PsaL-mediated assembly of the PSI reaction center. [ABSTRACT FROM AUTHOR]

ABSTRACT Warm temperatures accelerate plant growth, but the underlying molecular mechanism is not fully understood. Here, we show that increasing the temperature from 22°C to 28°C rapidly activates proliferation in the apical shoot and root meristems of wild‐type Arabidopsis seedlings. We found that one of the central regulators of cell proliferation, the cell cycle inhibitor RETINOBLASTOMA‐RELATED (RBR), is suppressed by warm temperatures. RBR became hyper‐phosphorylated at a conserved CYCLIN‐DEPENDENT KINASE (CDK) site in young seedlings growing at 28°C, in parallel with the stimulation of the expressions of the regulatory CYCLIN D/A subunits of CDK(s). Interestingly, while under warm temperatures ectopic RBR slowed down the acceleration of cell proliferation, it triggered elongation growth of post‐mitotic cells in the hypocotyl. In agreement, the central regulatory genes of thermomorphogenic response, including PIF4 and PIF7, as well as their downstream auxin biosynthetic YUCCA genes (YUC1‐2 and YUC8‐9) were all up‐regulated in the ectopic RBR expressing line but down‐regulated in a mutant line with reduced RBR level. We suggest that RBR has both canonical and non‐canonical functions under warm temperatures to control proliferative and elongation growth, respectively. [ABSTRACT FROM AUTHOR]

The promoter of the RECEPTOR-LIKE CYTOPLASMIC KINASE VI_A2 (RLCK VI_A2) gene contains nine binding sites for the REPLUMLESS (RPL) transcription factor. In agreement, the expression of the kinase gene was strongly downregulated in the rpl-4 mutant. Comparing phenotypes of loss-of-function mutants, it was revealed that both genes are involved in stem growth, phyllotaxis, organization of the vascular tissues, and the replum, highlighting potential functional interactions. The expression of the RLCKVI_A2 gene from the constitutive 35S promoter could not complement the rpl-4 phenotypes but exhibited a dominant positive effect on stem growth and affected vascular differentiation and organization. The results also indicated that the number of vascular bundles is regulated independently from stem thickness. Although our study cannot demonstrate a direct link between the RPL and RLVKVI_A2 genes, it highlights the significance of the proper developmental regulation of the RLCKVI_A2 promoter for balanced stem development. [ABSTRACT FROM AUTHOR]

In photosynthetic organisms, carotenoids (carotenes and xanthophylls) are important for light harvesting, photoprotection and structural stability of a variety of pigment–protein complexes. Here, we investigated the consequences of altered carotenoid composition for the functional organization of photosynthetic complexes in wild-type and various mutant strains of the cyanobacterium Synechocystis sp. PCC 6803. Although it is generally accepted that xanthophylls do not play a role in cyanobacterial photosynthesis in low-light conditions, we have found that the absence of xanthophylls leads to reduced oligomerization of photosystems I and II. This is remarkable because these complexes do not bind xanthophylls. Oligomerization is even more disturbed in crtH mutant cells, which show limited carotenoid synthesis; in these cells also the phycobilisomes are distorted despite the fact that these extramembranous light-harvesting complexes do not contain carotenoids. The number of phycocyanin rods connected to the phycobilisome core is strongly reduced leading to high amounts of unattached phycocyanin units. In the absence of carotenoids the overall organization of the thylakoid membranes is disturbed: Photosystem II is not formed, photosystem I hardly oligomerizes and the assembly of phycobilisomes remains incomplete. These data underline the importance of carotenoids in the structural and functional organization of the cyanobacterial photosynthetic machinery. [ABSTRACT FROM AUTHOR]

In cyanobacteria, phycobilisomes (PBS) serve as peripheral light-harvesting complexes of the two photosystems, extending their antenna size and the wavelength range of photons available for photosynthesis. The abundance of PBS, the number of phycobiliproteins they contain, and their light-harvesting function are dynamically adjusted in response to the physiological conditions. PBS are also thought to be involved in state transitions that maintain the excitation balance between the two photosystems. Unlike its eukaryotic counterpart, PSI is trimeric in many cyanobacterial species and the physiological significance of this is not well understood. Here, we compared the composition and light-harvesting function of PBS in cells of Synechocystis sp. PCC 6803, which has primarily trimeric PSI, and the ΔpsaL mutant, which lacks the PsaL subunit of PSI and is unable to form trimers. We also investigated a mutant additionally lacking the PsaJ and PsaF subunits of PSI. Both strains with monomeric PSI accumulated significantly more allophycocyanin per chlorophyll, indicating higher abundance of PBS. On the other hand, a higher phycocyanin:allophycocyanin ratio in the wild type suggests larger PBS or the presence of APC-less PBS (CpcL-type) that are not assembled in cells with monomeric PSI. Steady-state and time-resolved fluorescence spectroscopy at room temperature and 77 K revealed that PSII receives more energy from the PBS at the expense of PSI in cells with monomeric PSI, regardless of the presence of PsaF. Taken together, these results show that the oligomeric state of PSI impacts the excitation energy flow in Synechocystis. [ABSTRACT FROM AUTHOR]

Apolipoprotein E (ApoE) isoforms exert intricate effects on cellular physiology beyond lipid transport and metabolism. ApoEs influence the onset of Alzheimer's disease (AD) in an isoform-dependent manner: ApoE4 increases AD risk, while ApoE2 decreases it. Previously we demonstrated that syndecans, a transmembrane proteoglycan family with increased expression in AD, trigger the aggregation and modulate the cellular uptake of amyloid beta (Aβ). Utilizing our previously established syndecan-overexpressing cellular assays, we now explore how the interplay of ApoEs with syndecans contributes to key events, namely uptake and aggregation, in Aβ pathology. The interaction of ApoEs with syndecans indicates isoform-specific characteristics arising beyond the frequently studied ApoE–heparan sulfate interactions. Syndecans, and among them the neuronal syndecan-3, increased the cellular uptake of ApoEs, especially ApoE2 and ApoE3, while ApoEs exerted opposing effects on syndecan-3-mediated Aβ uptake and aggregation. ApoE2 increased the cellular internalization of monomeric Aβ, hence preventing its extracellular aggregation, while ApoE4 decreased it, thus helping the buildup of extracellular plaques. The contrary effects of ApoE2 and ApoE4 remained once Aβ aggregated: while ApoE2 reduced the uptake of Aβ aggregates, ApoE4 facilitated it. Fibrillation studies also revealed ApoE4′s tendency to form fibrillar aggregates. Our results uncover yet unknown details of ApoE cellular biology and deepen our molecular understanding of the ApoE-dependent mechanism of Aβ pathology. [ABSTRACT FROM AUTHOR]

The plant-specific receptor-like cytoplasmic kinases (RLCKs) form a large, poorly characterized family. Members of the RLCK VI_A class of dicots have a unique characteristic: their activity is regulated by Rho-of-plants (ROP) GTPases. The biological function of one of these kinases was investigated using a T-DNA insertion mutant and RNA interference. Loss of RLCK VI_A2 function resulted in restricted cell expansion and seedling growth. Although these phenotypes could be rescued by exogenous gibberellin, the mutant did not exhibit lower levels of active gibberellins nor decreased gibberellin sensitivity. Transcriptome analysis confirmed that gibberellin is not the direct target of the kinase; its absence rather affected the metabolism and signalling of other hormones such as auxin. It is hypothesized that gibberellins and the RLCK VI_A2 kinase act in parallel to regulate cell expansion and plant growth. Gene expression studies also indicated that the kinase might have an overlapping role with the transcription factor circuit (PIF4-BZR1-ARF6) controlling skotomorphogenesis-related hypocotyl/cotyledon elongation. Furthermore, the transcriptomic changes revealed that the loss of RLCK VI_A2 function alters cellular processes that are associated with cell membranes, take place at the cell periphery or in the apoplast, and are related to cellular transport and/or cell wall reorganisation. [ABSTRACT FROM AUTHOR]

Scientific evidence suggests that α-synuclein and tau have prion-like properties and that prion-like spreading and seeding of misfolded protein aggregates constitutes a central mechanism for neurodegeneration. Heparan sulfate proteoglycans (HSPGs) in the plasma membrane support this process by attaching misfolded protein fibrils. Despite of intense studies, contribution of specific HSPGs to seeding and spreading of α-synuclein and tau has not been explored yet. Here we report that members of the syndecan family of HSPGs mediate cellular uptake of α-synuclein and tau fibrils via a lipid-raft dependent and clathrin-independent endocytic route. Among syndecans, the neuron predominant syndecan-3 exhibits the highest affinity for both α-synuclein and tau. Syndecan-mediated internalization of α-synuclein and tau depends heavily on conformation as uptake via syndecans start to dominate once fibrils are formed. Overexpression of syndecans, on the other hand, reduces cellular uptake of monomeric α-synuclein and tau, yet exerts a fibril forming effect on both proteins. Data obtained from syndecan overexpressing cellular models presents syndecans, especially the neuron predominant syndecan-3, as important mediators of seeding and spreading of α-synuclein and tau and reveal how syndecans contribute to fundamental molecular events of α-synuclein and tau pathology. [ABSTRACT FROM AUTHOR]

Phosphatidylglycerol is an essential phospholipid for photosynthesis and other cellular processes. We investigated the role of phosphatidylglycerol in cell division and metabolism in a phophatidylglycerol-auxotrophic strain of Synechococcus PCC7942. Here we show that phosphatidylglycerol is essential for the photosynthetic electron transfer and for the oligomerisation of the photosynthetic complexes, notably, we revealed that this lipid is important for non-linear electron transport. Furthermore, we demonstrate that phosphatidylglycerol starvation elevated the expressions of proteins of nitrogen and carbon metabolism. Moreover, we show that phosphatidylglycerol-deficient cells changed the morphology, became elongated, the FtsZ ring did not assemble correctly, and subsequently the division was hindered. However, supplementation with phosphatidylglycerol restored the ring-like structure at the mid-cell region and the normal cell size, demonstrating the phosphatidylglycerol is needed for normal septum formation. Taken together, central roles of phosphatidylglycerol were revealed; it is implicated in the photosynthetic activity, the metabolism and the fission of bacteria. [ABSTRACT FROM AUTHOR]

In the thylakoid membranes of the mesophilic cyanobacterium Synechocystis PCC6803, PSI reaction centers (RCs) are organized as monomers and trimers. PsaL, a 16 kDa hydrophobic protein, a subunit of the PSI RC, was previously identified as crucial for the formation of PSI trimers. In this work, the physiological effects accompanied by PSI oligomerization were studied using a PsaL-deficient mutant (ΔpsaL), not able to form PSI trimers, grown at various temperatures. We demonstrate that in wild-type Synechocystis, the monomer to trimer ratio depends on the growth temperature. The inactivation of the psaL gene in Synechocystis grown phototropically at 30C induces profound morphological changes, including the accumulation of glycogen granules localized in the cytoplasm, resulting in the separation of particular thylakoid layers. The carotenoid composition in ΔpsaL shows that PSI monomerization leads to an increased accumulation of myxoxantophyll, zeaxanthin and echinenone irrespective of the temperature conditions. These xanthophylls are formed at the expense of b-carotene. The measured H2O→CO2 oxygen evolution rates in the ΔpsaL mutant are higher than those observed in the wild type, irrespective of the growth temperature. Moreover, circular dichroism spectroscopy in the visible range reveals that a peak attributable to long-wavelength-absorbing carotenoids is apparently enhanced in the trimer-accumulating wild-type cells. These results suggest that specific carotenoids are accompanied by the accumulation of PSI oligomers and play a role in the formation of PSI oligomer structure. [ABSTRACT FROM AUTHOR]

Abstract: Functional roles of an anionic lipid phosphatidylglycerol (PG) were studied in pgsA-gene-inactivated and cdsA-gene-inactivated/phycobilisome-less mutant cells of a cyanobacterium Synechocystis sp. PCC 6803, which can grow only in PG-supplemented media. 1) A few days of PG depletion suppressed oxygen evolution of mutant cells supported by p-benzoquinone (BQ). The suppression was recovered slowly in a week after PG re-addition. Measurements of fluorescence yield indicated the enhanced sensitivity of QB to the inactivation by BQ. It is assumed that the loss of low-affinity PG (PGL) enhances the affinity for BQ that inactivates QB. 2) Oxygen evolution without BQ, supported by the endogenous electron acceptors, was slowly suppressed due to the direct inactivation of QB during 10days of PG depletion, and was recovered rapidly within 10h upon the PG re-addition. It is concluded that the loss of high-affinity PG (PGH) displaces QB directly. 3) Electron microscopy images of PG-depleted cells showed the specific suppression of division of mutant cells, which had developed thylakoid membranes attaching phycobilisomes (PBS). 4) Although the PG-depletion for 14days decreased the chlorophyll/PBS ratio to about 1/4, florescence spectra/lifetimes were not modified indicating the flexible energy transfer from PBS to different numbers of PSII. Longer PG-depletion enhanced allophycocyanin fluorescence at 683nm with a long 1.2ns lifetime indicating the suppression of energy transfer from PBS to PSII. 5) Action sites of PGH, PGL and other PG molecules on PSII structure are discussed. [Copyright &y& Elsevier]

The crtB gene of Synechocystis sp. PCC 6803, encoding phytoene synthase, was inactivated in the ΔcrtH mutant to generate a carotenoidless ΔcrtH/B double mutant. ΔcrtH mutant cells were used because they had better transformability than wild-type cells, most probably due to their adaptation to partial carotenoid deficiency. Cells of the ΔcrtH/B mutant were light sensitive and could grow only under light-activated heterotrophic growth conditions in the presence of glucose. Carotenoid deficiency did not significantly affect the cellular content of phycobiliproteins while the chlorophyll content of the mutant cells decreased. The mutant cells exhibited no oxygen-evolving activity, suggesting the absence of photochemically active PSII complexes. This was confirmed by 2D electrophoresis of photosynthetic membrane complexes. Analyses identified only a small amount of a non-functional PSII core complex lacking CP43, while the monomeric and dimeric PSII core complexes were absent. On the other hand, carotenoid deficiency did not prevent formation of the cytochrome b6f complex and PSI, which predominantly accumulated in the monomeric form. Radioactive labeling revealed very limited synthesis of inner PSII antennae, CP47 and especially CP43. Thus, carotenoids are indispensable constituents of the photosynthetic apparatus, being essential not only for antioxidative protection but also for the efficient synthesis and accumulation of photosynthetic proteins and especially that of PSII antenna subunits. [ABSTRACT FROM PUBLISHER]

Abstract: To analyze the role of phosphatidylglycerol (PG) in photosynthetic membranes of cyanobacteria we used two mutants of Synechocystis sp. PCC6803: the PAL mutant which has no phycobilisomes and shows a high PSII/PSI ratio, and a mutant derived from it by inactivating its cdsA gene encoding cytidine 5''-diphosphate diacylglycerol synthase, a key enzyme in PG synthesis. In a medium supplemented with PG the PAL/ΔcdsA mutant cells grew photoautotrophically. Depletion of PG in the medium resulted (a) in an arrest of cell growth and division, (b) in a slowdown of electron transfer from the acceptor QA to QB in PSII and (c) in a modification of chlorophyll fluorescence curve. The depletion of PG affected neither the redox levels of QA nor the S2 state of the oxygen-evolving manganese complex, as indicated by thermoluminescence studies. Two-dimensional PAGE showed that in the absence of PG (a) the PSII dimer was decomposed into monomers, and (b) the CP43 protein was detached from a major part of the PSII core complex. [35S]-methionine labeling confirmed that PG depletion did not block de novo synthesis of the PSII proteins. We conclude that PG is required for the binding of CP43 within the PSII core complex. [Copyright &y& Elsevier]

In Part I, by using 31P-NMR spectroscopy, we have shown that isolated granum and stroma thylakoid membranes (TMs), in addition to the bilayer, display two isotropic phases and an inverted hexagonal (HII) phase; saturation transfer experiments and selective effects of lipase and thermal treatments have shown that these phases arise from distinct, yet interconnectable structural entities. To obtain information on the functional roles and origin of the different lipid phases, here we performed spectroscopic measurements and inspected the ultrastructure of these TM fragments. Circular dichroism, 77 K fluorescence emission spectroscopy, and variable chlorophyll-a fluorescence measurements revealed only minor lipase- or thermally induced changes in the photosynthetic machinery. Electrochromic absorbance transients showed that the TM fragments were re-sealed, and the vesicles largely retained their impermeabilities after lipase treatments—in line with the low susceptibility of the bilayer against the same treatment, as reflected by our 31P-NMR spectroscopy. Signatures of HII-phase could not be discerned with small-angle X-ray scattering—but traces of HII structures, without long-range order, were found by freeze-fracture electron microscopy (FF-EM) and cryo-electron tomography (CET). EM and CET images also revealed the presence of small vesicles and fusion of membrane particles, which might account for one of the isotropic phases. Interaction of VDE (violaxanthin de-epoxidase, detected by Western blot technique in both membrane fragments) with TM lipids might account for the other isotropic phase. In general, non-bilayer lipids are proposed to play role in the self-assembly of the highly organized yet dynamic TM network in chloroplasts. [ABSTRACT FROM AUTHOR]

The increasing rate of fungal infections causes global problems not only in human healthcare but agriculture as well. To combat fungal pathogens limited numbers of antifungal agents are available therefore alternative drugs are needed. Antimicrobial peptides are potent candidates because of their broad activity spectrum and their diverse mode of actions. The model legume Medicago truncatula produces >700 nodule specific cysteine-rich (NCR) peptides in symbiosis and many of them have in vitro antimicrobial activities without considerable toxicity on human cells. In this work we demonstrate the anticandidal activity of the NCR335 and NCR169 peptide derivatives against five Candida species by using the micro-dilution method, measuring inhibition of biofilm formation with the XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay, and assessing the morphological change of dimorphic Candida species by microscopy. We show that both the N- and C-terminal regions of NCR335 possess anticandidal activity as well as the C-terminal sequence of NCR169. The active peptides inhibit biofilm formation and the yeast-hypha transformation. Combined treatment of C. auris with peptides and fluconazole revealed synergistic interactions and reduced 2-8-fold the minimal inhibitory concentrations. Our results demonstrate that shortening NCR peptides can even enhance and broaden their anticandidal activity and therapeutic potential. [ABSTRACT FROM AUTHOR]

Intraneuronal accumulation of amyloid-β(1-42) (Aβ1-42) is one of the earliest signs of Alzheimer's disease (AD). Cell surface heparan sulfate proteoglycans (HSPGs) have profound influence on the cellular uptake of Aβ1-42 by mediating its attachment and subsequent internalization into the cells. Colocalization of amyloid plaques with members of the syndecan family of HSPGs, along with the increased expression of syndecan-3 and -4 have already been reported in postmortem AD brains. Considering the growing evidence on the involvement of syndecans in the pathogenesis of AD, we analyzed the contribution of syndecans to cellular uptake and fibrillation of Aβ1-42. Among syndecans, the neuron specific syndecan-3 isoform increased cellular uptake of Aβ1-42 the most. Kinetics of Aβ1-42 uptake also proved to be fairly different among SDC family members: syndecan-3 increased Aβ1-42 uptake from the earliest time points, while other syndecans facilitated Aβ1-42 internalization at a slower pace. Internalized Aβ1-42 colocalized with syndecans and flotillins, highlighting the role of lipid-rafts in syndecan-mediated uptake. Syndecan-3 and 4 also triggered fibrillation of Aβ1-42, further emphasizing the pathophysiological relevance of syndecans in plaque formation. Overall our data highlight syndecans, especially the neuron-specific syndecan-3 isoform, as important players in amyloid pathology and show that syndecans, regardless of cell type, facilitate key molecular events in neurodegeneration. [ABSTRACT FROM AUTHOR]