| Structural highlights
Function
[CALM_XENLA] Calmodulin mediates the control of a large number of enzymes, ion channels and other proteins by Ca(2+). Among the enzymes to be stimulated by the calmodulin-Ca(2+) complex are a number of protein kinases and phosphatases. [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.[1] [2] [3]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Ca(2+) signalling in neurons through calmodulin (CaM) has a prominent function in regulating synaptic vesicle trafficking, transport, and fusion. Importantly, Ca(2+)-CaM binds a conserved region in the priming proteins Munc13-1 and ubMunc13-2 and thus regulates synaptic neurotransmitter release in neurons in response to residual Ca(2+) signals. We solved the structure of Ca(2+)(4)-CaM in complex with the CaM-binding domain of Munc13-1, which features a novel 1-5-8-26 CaM-binding motif with two separated mobile structural modules, each involving a CaM domain. Photoaffinity labelling data reveal the same modular architecture in the complex with the ubMunc13-2 isoform. The N-module can be dissociated with EGTA to form the half-loaded Munc13/Ca(2+)(2)-CaM complex. The Ca(2+) regulation of these Munc13 isoforms can therefore be explained by the modular nature of the Munc13/Ca(2+)-CaM interactions, where the C-module provides a high-affinity interaction activated at nanomolar [Ca(2+)](i), whereas the N-module acts as a sensor at micromolar [Ca(2+)](i). This Ca(2+)/CaM-binding mode of Munc13 likely constitutes a key molecular correlate of the characteristic Ca(2+)-dependent modulation of short-term synaptic plasticity.
Modular architecture of Munc13/calmodulin complexes: dual regulation by Ca2+ and possible function in short-term synaptic plasticity.,Rodriguez-Castaneda F, Maestre-Martinez M, Coudevylle N, Dimova K, Junge H, Lipstein N, Lee D, Becker S, Brose N, Jahn O, Carlomagno T, Griesinger C EMBO J. 2010 Feb 3;29(3):680-91. Epub 2009 Dec 10. PMID:20010694[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Betz A, Ashery U, Rickmann M, Augustin I, Neher E, Sudhof TC, Rettig J, Brose N. Munc13-1 is a presynaptic phorbol ester receptor that enhances neurotransmitter release. Neuron. 1998 Jul;21(1):123-36. PMID:9697857
- ↑ Betz A, Thakur P, Junge HJ, Ashery U, Rhee JS, Scheuss V, Rosenmund C, Rettig J, Brose N. Functional interaction of the active zone proteins Munc13-1 and RIM1 in synaptic vesicle priming. Neuron. 2001 Apr;30(1):183-96. PMID:11343654
- ↑ Rhee JS, Betz A, Pyott S, Reim K, Varoqueaux F, Augustin I, Hesse D, Sudhof TC, Takahashi M, Rosenmund C, Brose N. Beta phorbol ester- and diacylglycerol-induced augmentation of transmitter release is mediated by Munc13s and not by PKCs. Cell. 2002 Jan 11;108(1):121-33. PMID:11792326
- ↑ Rodriguez-Castaneda F, Maestre-Martinez M, Coudevylle N, Dimova K, Junge H, Lipstein N, Lee D, Becker S, Brose N, Jahn O, Carlomagno T, Griesinger C. Modular architecture of Munc13/calmodulin complexes: dual regulation by Ca2+ and possible function in short-term synaptic plasticity. EMBO J. 2010 Feb 3;29(3):680-91. Epub 2009 Dec 10. PMID:20010694 doi:10.1038/emboj.2009.373
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