Structural and Functional Analysis of the CAPS SNARE-Binding Domain Required for SNARE Complex Formation and Exocytosis

Hao Zhou; Ziqing Wei; Shen Wang; Deqiang Yao; Rongguang Zhang; Cong Ma

doi:10.1016/j.celrep.2019.02.064

Structural and Functional Analysis of the CAPS SNARE-Binding Domain Required for SNARE Complex Formation and Exocytosis

Cell Rep. 2019 Mar 19;26(12):3347-3359.e6. doi: 10.1016/j.celrep.2019.02.064.

Authors

Hao Zhou¹, Ziqing Wei¹, Shen Wang¹, Deqiang Yao², Rongguang Zhang³, Cong Ma⁴

Affiliations

¹ Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China.
² National Center for Protein Science, Institute of Biochemistry and Cell Biology, Shanghai Institute for Biological Science, Chinese Academy of Sciences, 201203 Shanghai, China.
³ National Center for Protein Science, Institute of Biochemistry and Cell Biology, Shanghai Institute for Biological Science, Chinese Academy of Sciences, 201203 Shanghai, China; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101 Beijing, China.
⁴ Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China. Electronic address: cong.ma@hust.edu.cn.

PMID: 30893606
DOI: 10.1016/j.celrep.2019.02.064

Abstract

Exocytosis of synaptic vesicles and dense-core vesicles requires both the Munc13 and CAPS (Ca²⁺-dependent activator proteins for secretion) proteins. CAPS contains a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-binding region (called the DAMH domain), which has been found to be essential for SNARE-mediated exocytosis. Here we report a crystal structure of the CAPS-1 DAMH domain at 2.9-Å resolution and reveal a dual role of CAPS-1 in SNARE complex formation. CAPS-1 plays an inhibitory role dependent on binding of the DAMH domain to the MUN domain of Munc13-1, which hinders the ability of Munc13 to catalyze opening of syntaxin-1, inhibiting SNARE complex formation, and a chaperone role dependent on interaction of the DAMH domain with the syntaxin-1/SNAP-25 complex, which stabilizes the open conformation of Syx1, facilitating SNARE complex formation. Our results suggest that CAPS-1 facilitates SNARE complex formation via the DAMH domain in a manner dependent on sequential and cooperative interaction with Munc13-1 and SNARE proteins.

Keywords: CAPS; Munc13; SNARE; dense-core vesicle; exocytosis; synaptic vesicle.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Crystallography, X-Ray
HEK293 Cells
Humans
Nerve Tissue Proteins / chemistry*
Nerve Tissue Proteins / genetics
Nerve Tissue Proteins / metabolism
PC12 Cells
Protein Domains
Protein Structure, Quaternary
Rats
Sf9 Cells
Spodoptera
Synaptosomal-Associated Protein 25 / chemistry*
Synaptosomal-Associated Protein 25 / genetics
Synaptosomal-Associated Protein 25 / metabolism
Syntaxin 1 / chemistry*
Syntaxin 1 / genetics
Syntaxin 1 / metabolism

Substances

Nerve Tissue Proteins
SNAP25 protein, human
Synaptosomal-Associated Protein 25
Syntaxin 1
UNC13B protein, human