Delineating the Molecular Basis of the Calmodulin?bMunc13-2 Interaction by Cross-Linking/Mass Spectrometry-Evidence for a Novel CaM Binding Motif in bMunc13-2.

ABSTRACT: Exploring the interactions between the Ca2+ binding protein calmodulin (CaM) and its target proteins remains a challenging task. Members of the Munc13 protein family play an essential role in short-term synaptic plasticity, modulated via the interaction with CaM at the presynaptic compartment. In this study, we focus on the bMunc13-2 isoform expressed in the brain, as strong changes in synaptic transmission were observed upon its mutagenesis or deletion. The CaM?bMunc13-2 interaction was previously characterized at the molecular level using short bMunc13-2-derived peptides only, revealing a classical 1?5?10 CaM binding motif. Using larger protein constructs, we have now identified for the first time a novel and unique CaM binding site in bMunc13-2 that contains an N-terminal extension of a classical 1?5?10 CaM binding motif. We characterize this motif using a range of biochemical and biophysical methods and highlight its importance for the CaM?bMunc13-2 interaction.

SUBMITTER: Piotrowski C 

PROVIDER: S-EPMC7017353 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature