Rabphilin-3A对Rab3A小GTP结合蛋白的GDP/GTP交换反应刺激活性。

GDP/GTP exchange reaction-stimulating activity of Rabphilin-3A for Rab3A small GTP-binding protein.

作者信息

Fujita Y, Sasaki T, Araki K, Takahashi K, Imazumi K, Kato M, Matsuura Y, Takai Y

机构信息

Department of Molecular Biology and Biochemistry, Osaka University Medical School, Suita, Japan.

出版信息

FEBS Lett. 1994 Oct 10;353(1):67-70. doi: 10.1016/0014-5793(94)01015-3.

DOI:10.1016/0014-5793(94)01015-3

PMID:7926025

Abstract

Rabphilin-3A is a putative target protein for Rab3A, a small GTP-binding protein particularly implicated in neurotransmitter release. Rabphilin-3A interacts more preferentially with GTP-Rab3A than with GDP-Rab3A. Moreover, Rabphilin-3A shows a weak activity to stimulate the GTPase activity of Rab3A and a strong activity to inhibit the Rab3A GTPase-activating protein (GAP)-stimulated GTPase activity of Rab3A. Here, we show that Rabphilin-3A has another activity to stimulate the GDP/GTP exchange reaction of Rab3A. Rabphilin-3A may keep Rab3A continuously in the GTP-bound form by converting again GDP-Rab3A, which may be converted from GTP-Rab3A by Rab3A GAP, to GTP-Rab3A, until the function of Rab3A is accomplished.

摘要

Rabphilin-3A是小GTP结合蛋白Rab3A的一个假定靶蛋白，Rab3A特别涉及神经递质释放。Rabphilin-3A与GTP-Rab3A的相互作用比与GDP-Rab3A的相互作用更具选择性。此外，Rabphilin-3A显示出较弱的刺激Rab3A的GTP酶活性的活性以及较强的抑制Rab3A的GTP酶激活蛋白（GAP）刺激的Rab3A的GTP酶活性的活性。在此，我们表明Rabphilin-3A具有另一种刺激Rab3A的GDP/GTP交换反应的活性。Rabphilin-3A可能通过将可能由Rab3A GAP从GTP-Rab3A转化而来的GDP-Rab3A再次转化为GTP-Rab3A，从而使Rab3A持续保持在GTP结合形式，直到Rab3A的功能完成。