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

FEBS Letters

Araki, Keishi¹  Takai, Yoshimi¹  Imazumi, Katsunori¹  Kato, Masaki¹  Takahashi, Kazuo¹  Matsuura, Yoshiharu²  Fujita, Yasuyuki¹  Sasaki, Takuya¹ 

[1] Department of Molecular Biology and Biochemistry, Osaka University Medical School, 2-2 Yamada-oka, Suita 565, Japan;Department of Virology II, National Institute of Health, Tokyo 162, Japan

关键词: Small G protein;    Rab3A;    Rabphilin-3A;    GEP activity;    NSF;    N-ethylmaleimide-sensitive fusion protein;    SNAP;    soluble NSF attachment protein;    SNARE;    SNAP receptor;    GAP;    GTPase-activating protein;    GDI;    GDP dissociation inhibitor;    GRF;    guanine nucleotide releasing factor;    GIP;    GAP inhibiting protein;    GEP;    GDP/GTP exchange protein;    GTPγS;    guanosine 5′-(3-O-thio) triphosphate;    G protein;    GTP-binding protein;    GDS;    GDP dissociation stimulator;   

DOI  :  10.1016/0014-5793(94)01015-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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. Rabphifin-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.

【 授权许可】

Unknown