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
oleh: Christine Piotrowski, Rocco Moretti, Christian H. Ihling, André Haedicke, Thomas Liepold, Noa Lipstein, Jens Meiler, Olaf Jahn, Andrea Sinz
| Format: | Article |
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| Diterbitkan: | MDPI AG 2020-01-01 |
Deskripsi
Exploring the interactions between the Ca<sup>2+</sup> 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 <i>N</i>-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.