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Neuronal calcium sensor‐1 facilitates neuronal exocytosis through phosphatidylinositol 4‐kinase
Author(s) -
Zheng Qian,
Bobich Joseph A.,
Vidugiriene Jolanta,
McFadden Susanne C.,
Thomas Fairwell,
Roder John,
Jeromin Andreas
Publication year - 2005
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2004.02897.x
Subject(s) - neurotransmitter , free nerve ending , phosphatidylinositol , exocytosis , wortmannin , glutamate receptor , biophysics , chemistry , membrane , synaptosome , biochemistry , microbiology and biotechnology , phosphorylation , biology , endocrinology , receptor
This work tested the theory that neuronal calcium sensor‐1 (NCS‐1) has effects on neurotransmitter release beyond its actions on membrane channels. We used nerve‐ending preparations where membrane channels are bypassed through membrane permeabilization made by mechanical disruption or streptolysin‐O. Nerve ending NCS‐1 and phosphatidylinositol 4‐kinase (PI4K) are largely or entirely particulate, so their concentrations in nerve endings remain constant after breaching the membrane. Exogenous, myristoylated NCS‐1 stimulated nerve ending phosphatidylinositol 4‐phosphate [PI(4)P] synthesis, but non‐myristoylated‐NCS‐1 did not. The N‐terminal peptide of NCS‐1 interfered with PI(4)P synthesis, and with spontaneous and Ca 2+ ‐evoked release of both [ 3 H]‐norepinephrine (NA) and [ 14 C]‐glutamate (glu) in a concentration‐dependent manner. An antibody raised against the N‐terminal of NCS‐1 inhibited perforated nerve ending PI(4)P synthesis, but the C‐terminal antibody had no effects. Antibodies against the N‐ and C‐termini of NCS‐1 caused significant increases in mini/spontaneous/stimulation‐independent release of [ 3 H]‐NA from perforated nerve endings, but had no effect on [ 14 C]‐glu release. These results support the idea that NCS‐1 facilitates nerve ending neurotransmitter release and phosphoinositide production via PI4K and localizes these effects to the N‐terminal of NCS‐1. Combined with previous work on the regulation of channels by NCS‐1, the data are consistent with the hypothesis that a NCS‐1–PI4K (NP, neuropotentiator) complex may serve as an essential linker between lipid and protein metabolism to regulate membrane traffic and co‐ordinate it with ion fluxes and plasticity in the nerve ending.