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  • Phosphorylation of Syntaxin-1a by casein kinase 2α regulates pre-synaptic vesicle exocytosis from the reserve pool.

Phosphorylation of Syntaxin-1a by casein kinase 2α regulates pre-synaptic vesicle exocytosis from the reserve pool.

Journal of neurochemistry (2020-08-28)
Vanilla Hua Shi, Tim J Craig, Paul Bishop, Yasuko Nakamura, Dan Rocca, Kevin A Wilkinson, Jeremy M Henley
ABSTRACT

The t-soluble NSF-attachment protein receptor protein Syntaxin-1a (Stx-1a) is abundantly expressed at pre-synaptic terminals where it plays a critical role in the exocytosis of neurotransmitter-containing synaptic vesicles. Stx-1a is phosphorylated by Casein kinase 2α (CK2α) at Ser14, which has been proposed to regulate the interaction of Stx-1a and Munc-18 to control of synaptic vesicle priming. However, the role of CK2α in synaptic vesicle dynamics remains unclear. Here, we show that CK2α over-expression reduces evoked synaptic vesicle release. Furthermore, shRNA-mediated knockdown of CK2α in primary hippocampal neurons strongly enhanced vesicle exocytosis from the reserve pool, with no effect on the readily releasable pool of primed vesicles. In neurons in which endogenous Stx-1a was knocked down and replaced with a CK2α phosphorylation-deficient mutant, Stx-1a(D17A), vesicle exocytosis was also increased. These results reveal a previously unsuspected role of CK2α phosphorylation in specifically regulating the reserve synaptic vesicle pool, without changing the kinetics of release from the readily releasable pool.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-Rat IgG (whole molecule)−Peroxidase antibody produced in rabbit, affinity isolated antibody, buffered aqueous solution
Sigma-Aldrich
Poly-L-lysine hydrobromide, mol wt 30,000-70,000
Sigma-Aldrich
Anti-Mouse IgG (Fab specific)–Peroxidase antibody produced in goat, affinity isolated antibody, buffered aqueous solution
Sigma-Aldrich
Anti-Syntaxin antibody, Mouse monoclonal, clone HPC-1, purified from hybridoma cell culture