Journal Article

Two Distinct Mechanisms Underlie the Stimulation of Neurotransmitter Release by Phorbol Esters in Clonal Rat Phechromocytoma PC12 Cells

Satoshi Iwasaki, Masakazu Kataoka, Mariko Sekiguchi, Yoji Shimazaki, Kazuki Sato and Masami Takahasi

in The Journal of Biochemistry

Published on behalf of The Japanese Biochemical Society

Volume 128, issue 3, pages 407-414
Published in print September 2000 | ISSN: 0021-924X
Published online September 2000 | e-ISSN: 1756-2651 | DOI:

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Phorbol ester treatment induces the phosphorylation of SNAP-25 at Ser187 and the potentiation of Ca2+ induced dopamine (DA) and acetylcholine (Ach) release from PC12 cell. In order to evaluate the functional consequences of phosphorylation, quantitative analysis was carried out using an anti-phosphopeptide antibody that specifically recognizes SNAP-25 phosphorylated at Ser187. DA and ACh release, assayed in low-K+ as well as high-K+ solution increased by treating the cells with phorbol-12-myristate-13-acetate (PMA); however, stimulation of high-K+-dependent release occurred at lower concentrations and with shorter exposures to PMA than that of the basal release in low-K+ solution. The PMA-induced phosphorylation of SNAP-25 did not correlate with the potentiation of high-k+ dependent neurotransmitter release. The potentiation of high K+-dependent DA release by phorbol 12,13 diacetate (PDA), a water soluble phorbol ester, almost completely disappeared within 1 min after washing PDA in the Presence of okadaic acid, conditions under which the phosphorylation of SNAP-25 persisted for at least 15 min. PMA-induced phosphorylation of SNAP-25 was inhibited by staurosporine, however, the potentiation of high-K+-dependent Da release was suppressed only partially. These results indicate that protein kinase activation does not account for a large fraction of the phorbol ester-induced potentiation of depolarization-dependent neurotransmitter release from PC12 cells

Keywords: neurotransmitter release; phorbol ester; phosphorylation; PKC; SNAP-25

Journal Article.  0 words. 

Subjects: Biochemistry