Structural and mechanistic insights into secretagogin-mediated exocytosis.
Proc Natl Acad Sci U S A
; 117(12): 6559-6570, 2020 03 24.
Article
in En
| MEDLINE
| ID: mdl-32156735
ABSTRACT
Secretagogin (SCGN) is a hexa-EF-hand protein that is highly expressed in the pancreas, brain, and gastrointestinal tract. SCGN is known to modulate regulated exocytosis in multiple cell lines and tissues; however, its exact functions and underlying mechanisms remain unclear. Here, we report that SCGN interacts with the plasma membrane SNARE SNAP-25, but not the assembled SNARE complex, in a Ca2+-dependent manner. The crystal structure of SCGN in complex with a SNAP-25 fragment reveals that SNAP-25 adopts a helical structure and binds to EF-hands 5 and 6 of SCGN. SCGN strongly inhibits SNARE-mediated vesicle fusion in vitro by binding to SNAP-25. SCGN promotes the plasma membrane localization of SNAP-25, but not Syntaxin-1a, in SCGN-expressing cells. Finally, SCGN controls neuronal growth and brain development in zebrafish, likely via interacting with SNAP-25 or its close homolog, SNAP-23. Our results thus provide insights into the regulation of SNAREs and suggest that aberrant synapse functions underlie multiple neurological disorders caused by SCGN deficiency.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Exocytosis
/
Secretagogins
Limits:
Animals
/
Humans
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
2020
Document type:
Article
Affiliation country:
China