Synaptotagmin acts as the Ca(2+) sensor for neuronal exocytosis. The cytosolic domain of human synaptotagmin 1 is composed of tandem C2 domains: C2A and C2B. These C2 domains modulate the interaction of synaptotagmin with the phospholipid bilayer of the presynaptic terminus and effector proteins such as the SNARE complex. Human synaptotagmin C2A-C2B has been expressed as a glutathione-S-transferase fusion protein in Escherichia coli. The purification, crystallization and preliminary X-ray analysis of this protein are reported here. The crystals diffract to 2.7 A and belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 82.37, b = 86.31, c = 140.2 A. From self-rotation function analysis, there are two molecules in the asymmetric unit. The structure determination of the protein using this data is ongoing.
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http://dx.doi.org/10.1107/S1744309106029253 | DOI Listing |
Nat Commun
December 2024
Nanobiology Institute, Yale University, West Haven, CT, USA.
Neurotransmitters are released from synaptic vesicles with remarkable precision in response to presynaptic calcium influx but exhibit significant heterogeneity in exocytosis timing and efficacy based on the recent history of activity. This heterogeneity is critical for information transfer in the brain, yet its molecular basis remains poorly understood. Here, we employ a biochemically-defined fusion assay under physiologically relevant conditions to delineate the minimal protein machinery sufficient to account for various modes of calcium-triggered vesicle fusion dynamics.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
December 2024
Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
Plasma membrane repair (PMR) restores membrane integrity of cells, preventing cell death in vital organs, and has been studied extensively in skeletal muscle. Dysferlin, a sarcolemmal Ca-binding protein, plays a crucial role in PMR in skeletal muscle. Previous studies have suggested that PMR employs membrane trafficking and membrane fusion, similar to neurotransmission.
View Article and Find Full Text PDFBiophys J
December 2024
Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, CT; Nanobiology Institute, Yale University, West Haven, CT; Molecular Biophysics and Biochemistry, Yale University, New Haven, CT; Saints-Pères Paris Institute for the Neurosciences (SPPIN), Université de Paris, Centre National de la Recherche Scientifique (CNRS) UMR 8003, Paris, France; Wu Tsai Institute, Yale University. Electronic address:
Synaptotagmin-1 (Syt1) is a major calcium sensor for rapid neurotransmitter release in neurons and hormone release in many neuroendocrine cells. It possesses two tandem cytosolic C2 domains that bind calcium, negatively charged phospholipids, and the neuronal SNARE complex. Calcium binding to Syt1 triggers exocytosis, but how this occurs is not well understood.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China.
Extended-synaptotagmins (E-Syts) are proteins located on the endoplasmic reticulum (ER) that tether the ER to the plasma membrane (PM) and regulate their lipid homeostasis via its lipid transfer module, the synaptotagmin-like mitochondrial lipid-binding protein (SMP) domain. Here, we describe in vitro DNA nanostructure-assisted lipid transfer assays investigating how the SMP domain transports lipids between membranes and associates with the membranes to extract and release lipids. The lipid transfer signal was detected through fluorescence resonance energy transfer (FRET).
View Article and Find Full Text PDFNat Commun
December 2024
Department of Neurology, the Second Affiliated Hospital, Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.
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