2cjt

Structural Basis for a Munc13-1 Homodimer - Munc13-1 - RIM Heterodimer Switch: C2-domains as Versatile Protein-Protein Interaction Modules

spinqualitylabelsall models 2cjt, resolution 1.44Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2cjt is a 4 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.44Å Ligands: EDO, FMT Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function UN13A_RAT Plays a role in vesicle maturation during exocytosis as a target of the diacylglycerol second messenger pathway. Involved in neurotransmitter release by acting in synaptic vesicle priming prior to vesicle fusion and participates in the activity-dependent refilling of readily releasable vesicle pool (RRP). Essential for synaptic vesicle maturation in most excitatory/glutamatergic but not inhibitory/GABA-mediated synapses. Also involved in secretory granule priming in insulin secretion. Publication Abstract from PubMed C(2) domains are well characterized as Ca(2+)/phospholipid-binding modules, but little is known about how they mediate protein-protein interactions. In neurons, a Munc13-1 C(2)A-domain/RIM zinc-finger domain (ZF) heterodimer couples synaptic vesicle priming to presynaptic plasticity. We now show that the Munc13-1 C(2)A domain homodimerizes, and that homodimerization competes with Munc13-1/RIM heterodimerization. X-ray diffraction studies guided by nuclear magnetic resonance (NMR) experiments reveal the crystal structures of the Munc13-1 C(2)A-domain homodimer and the Munc13-1 C(2)A-domain/RIM ZF heterodimer at 1.44 A and 1.78 A resolution, respectively. The C(2)A domain adopts a beta-sandwich structure with a four-stranded concave side that mediates homodimerization, leading to the formation of an eight-stranded beta-barrel. In contrast, heterodimerization involves the bottom tip of the C(2)A-domain beta-sandwich and a C-terminal alpha-helical extension, which wrap around the RIM ZF domain. Our results describe the structural basis for a Munc13-1 homodimer-Munc13-1/RIM heterodimer switch that may be crucial for vesicle priming and presynaptic plasticity, uncovering at the same time an unexpected versatility of C(2) domains as protein-protein interaction modules, and illustrating the power of combining NMR spectroscopy and X-ray crystallography to study protein complexes. Structural basis for a Munc13-1 homodimer to Munc13-1/RIM heterodimer switch.,Lu J, Machius M, Dulubova I, Dai H, Sudhof TC, Tomchick DR, Rizo J PLoS Biol. 2006 Jul;4(7):e192. PMID:16732694 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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