Download MendeleyThe C 2 and PH domains of CAPS constitute an effective PI(4,5)P2-binding unit essential for Ca 2+ -regulated exocytosis.
Zhang, L., Li, L., Wei, Z., Zhou, H., Liu, H., Wang, S., Ren, Y., Dai, T., Wang, J., Hu, Z., Ma, C.(2023) Structure 31: 424
- PubMed: 36863339
- DOI: https://doi.org/10.1016/j.str.2023.02.004
- Primary Citation of Related Structures:
7VS3 - PubMed Abstract:
Ca 2+ -dependent activator proteins for secretion (CAPSs) are required for Ca 2+ -regulated exocytosis in neurons and neuroendocrine cells. CAPSs contain a pleckstrin homology (PH) domain that binds PI(4,5)P2-membrane. There is also a C 2 domain residing adjacent to the PH domain, but its function remains unclear. In this study, we solved the crystal structure of the CAPS-1 C 2 PH module. The structure showed that the C 2 and PH tandem packs against one another mainly via hydrophobic residues. With this interaction, the C 2 PH module exhibited enhanced binding to PI(4,5)P2-membrane compared with the isolated PH domain. In addition, we identified a new PI(4,5)P2-binding site on the C 2 domain. Disruption of either the tight interaction between the C 2 and PH domains or the PI(4,5)P2-binding sites on both domains significantly impairs CAPS-1 function in Ca 2+ -regulated exocytosis at the Caenorhabditis elegans neuromuscular junction (NMJ). These results suggest that the C 2 and PH domains constitute an effective unit to promote Ca 2+ -regulated exocytosis.
Organizational Affiliation:
Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
