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13 results on '"Piontek, Melissa C."'

6. Synaptotagmin-1 and Doc2b Exhibit Distinct Membrane-Remodeling Mechanisms

Author

Sorkin, Raya, Marchetti, Margherita, Logtenberg, Emma, Piontek, Melissa C., Kerklingh, Emma, Brand, Guy, Voleti, Rashmi, Rizo, Josep, Roos, Wouter H., Groffen, Alexander J., Wuite, Gijs J.L., Sorkin, Raya, Marchetti, Margherita, Logtenberg, Emma, Piontek, Melissa C., Kerklingh, Emma, Brand, Guy, Voleti, Rashmi, Rizo, Josep, Roos, Wouter H., Groffen, Alexander J., and Wuite, Gijs J.L.

Abstract

Synaptotagmin-1 (Syt1) is a calcium sensor protein that is critical for neurotransmission and is therefore extensively studied. Here, we use pairs of optically trapped beads coated with SNARE-free synthetic membranes to investigate Syt1-induced membrane remodeling. This activity is compared with that of Doc2b, which contains a conserved C2AB domain and induces membrane tethering and hemifusion in this cell-free model. We find that the soluble C2AB domain of Syt1 strongly affects the probability and strength of membrane-membrane interactions in a strictly Ca2+- and protein-dependent manner. Single-membrane loading of Syt1 yielded the highest probability and force of membrane interactions, whereas in contrast, Doc2b was more effective after loading both membranes. A lipid-mixing assay with confocal imaging reveals that both Syt1 and Doc2b are able to induce hemifusion; however, significantly higher Syt1 concentrations are required. Consistently, both C2AB fragments cause a reduction in the membrane-bending modulus, as measured by a method based on atomic force microscopy. This lowering of the energy required for membrane deformation may contribute to Ca2+-induced fusion.

Published
2020
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9. Synaptotagmin-1 and Doc2b Exhibit Distinct Membrane-Remodeling Mechanisms

Author

Sorkin, Raya, primary, Marchetti, Margherita, additional, Logtenberg, Emma, additional, Piontek, Melissa C., additional, Kerklingh, Emma, additional, Brand, Guy, additional, Voleti, Rashmi, additional, Rizo, Josep, additional, Roos, Wouter H., additional, Groffen, Alexander J., additional, and Wuite, Gijs J.L., additional

Published
2020
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10. The fluid membrane determines mechanics of erythrocyte extracellular vesicles and is softened in hereditary spherocytosis

Author

CDL Patiëntenzorg KC, Circulatory Health, CDL Nanomedicine, SCT patientenzorg, Child Health, Regenerative Medicine and Stem Cells, CDL Cluster Onderzoek en Onderwijs, Vorselen, Daan, van Dommelen, Susan M., Sorkin, Raya, Piontek, Melissa C., Schiller, Jürgen, Döpp, Sander T., Kooijmans, Sander A.A., van Oirschot, Brigitte A., Versluijs, Birgitta A., Bierings, Marc B., van Wijk, Richard, Schiffelers, Raymond M., Wuite, Gijs J.L., Roos, Wouter H., CDL Patiëntenzorg KC, Circulatory Health, CDL Nanomedicine, SCT patientenzorg, Child Health, Regenerative Medicine and Stem Cells, CDL Cluster Onderzoek en Onderwijs, Vorselen, Daan, van Dommelen, Susan M., Sorkin, Raya, Piontek, Melissa C., Schiller, Jürgen, Döpp, Sander T., Kooijmans, Sander A.A., van Oirschot, Brigitte A., Versluijs, Birgitta A., Bierings, Marc B., van Wijk, Richard, Schiffelers, Raymond M., Wuite, Gijs J.L., and Roos, Wouter H.

Published
2018

11. Membrane vesicles: Examination of biophysical properties with atomic force microscopy

Author

Piontek, Melissa C., Roos, Wouter H., and Molecular Biophysics

Subjects
atomic force microscopy, membrane vesicle, mechanics
Abstract

Extracellular vesicles (EVs) are not only intensively studied to increase our fundamental knowledge on their functioning, but also for diagnosis, therapeutics and drug delivery purposes. To improve the current and potential applications of EVs, a fundamental understanding of their stability, structure, and function is crucial. Such studies can be conducted at the single particle level to gain biological and physical information about the vesicles and the particle to particle variability. A suitable technique to investigate EVs under near- to physiological conditions is atomic force microscopy (AFM). Operated in liquid, it provides images of the EVs while mechanical properties of the particles can be obtained as well. Here we present our approach and the latest results in studying the structure and mechanics of these particles.

Published
2017

13. Atomic Force Microscopy: An Introduction.

Author

Piontek MC and Roos WH

Subjects
Nanotechnology methods, Microscopy, Atomic Force methods, Proteins chemistry
Abstract

Imaging of nano-sized particles and sample features is crucial in a variety of research fields. For instance in biological sciences, where it is paramount to investigate structures at the single particle level. Often two-dimensional images are not sufficient and further information such as topography and mechanical properties are required. Furthermore, to increase the biological relevance, it is desired to perform the imaging in close to physiological environments. Atomic force microscopy (AFM) meets these demands in an all-in-one instrument. It provides high-resolution images including surface height information leading to three-dimensional information on sample morphology. AFM can be operated both in air and in buffer solutions. Moreover, it has the capacity to determine protein and membrane material properties via the force spectroscopy mode. Here we discuss the principles of AFM operation and provide examples of how biomolecules can be studied. By including new approaches such as high-speed AFM (HS-AFM) we show how AFM can be used to study a variety of static and dynamic single biomolecules and biomolecular assemblies.

Published
2018
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