Spatial Organization of Biological Fuctions | BPS Thematic Meeting

Spatial Organization of Biological Functions Meeting

Thursday Speaker Abstracts

UNDERSTANDING SPATIAL PROTEIN-LIPID CLUSTERING THROUGH LIPID BILAYER NATIVE MASS SPECTROMETRY AND ITS ROLE IN NEURONAL COMMUNICATION Aniruddha Panda 1 ; 1 Tata Institute of Fundamental Research, Hyderabad, TCIS, Hyderabad, India The spatial clustering of proteins and lipids within cellular membranes is fundamental to all signaling events. Capturing these associations and understanding their molecular determinants requires a platform capable of directly detecting lipid-protein noncovalent interactions from lipid membranes. To address this, we have developed a novel lipid-bilayer native-mass spectrometry (nMS) platform. We have also integrated this with ion mobility-mass spectrometry (IM-MS), confocal microscopy, molecular dynamics (MD) simulations, and bulk fusion assay for the precise determination of the organization, stability of membrane protein-lipid complexes, and their functional role. We applied these platforms to understand how protein-lipid interactions regulate the spatial clustering of SNARE proteins and neurotransmitter release. Our findings demonstrate how specific binding of phosphatidylcholine (PC) and cholesterol (CHL) to VAMP2, the vesicular protein regulates the molecular clustering. IM-MS analysis indicated that increasing CHL in the membrane stabilizes VAMP2, which in turn stabilizes its cluster. Confocal microscopy experiments further demonstrate how these CHL-mediated associations between VAMP2 and lipids regulate the spatial clustering of VAMP in SV-like membranes. Finally, by combining these results with functional assays, we have elucidated how such organization of VAMP2 and lipids regulates the speed of neurotransmitter release. This work establishes a broadly applicable experimental platform for capturing membrane protein-lipid clustering and determining the specific molecular associations that drive these critical cellular processes. I have applied these platforms to VAMP7, another crucial vesicle-associated membrane protein which forms trimer and binds to both PC and CHL in bilayer. VAMP7 plays distinct roles in intracellular trafficking and fusion events, particularly in neuronal and immune cells. Understanding how these interactions influence VAMP7's conformation and its role in membrane fusion will further enhance our understanding of the diverse molecular mechanisms that govern vesicle fusion, offering potential insights into neurological disorders and cellular communication pathways.

TBD Zemer Gitai Princeton University, USA No Abstract

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