Download MendeleyModular 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.(2010) EMBO J 29: 680-691
- PubMed: 20010694
- DOI: https://doi.org/10.1038/emboj.2009.373
- Primary Citation of Related Structures:
2KDU - PubMed Abstract:
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.
Organizational Affiliation:
Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
