Rab3A GTPase-activating protein-inhibiting activity of Rabphilin-3A, a putative Rab3A target protein

S. Kishida, H. Shirataki, T. Sasaki, M. Kato, K. Kaibuchi, Y. Takai

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Rabphilin-3A is a putative target protein for Rab3A, a member of the small G protein superfamily that is implicated in regulated secretion, particularly in neurotransmitter release. Rabphilin-3A contains at least two functionally different domains: the N-terminal Rab3A-binding domain and the C-terminal C2 domain, which interacts with both Ca2+ and phospholipid. Because Rabphilin- 3A interacts preferentially with GTP-Rab3A rather than with GDP-Rab3A, we have examined here whether Rabphilin-3A affects the GTPase activity of Rab3A. Rabphilin-3A and its N-terminal fragment, but not its C-terminal fragment, very weakly stimulated the basal GTPase activity of Rab3A. However, Rabphilin-3A and its N-terminal fragment strongly inhibited the Rab3A GAP- stimulated GTPase activity of Rab3A. Ca2+ and phospholipid showed no effect on these activities of Rabphilin-3A. The physiological significance of the GAP activity of Rabphilin-3A is obscure, but it is likely that Rabphilin-3A inhibits Rab3A GAP activity and keeps Rab3A in the GTP-bound active form during its action as a target molecule for Rab3A.

Original languageEnglish
Pages (from-to)22259-22261
Number of pages3
JournalJournal of Biological Chemistry
Volume268
Issue number30
Publication statusPublished - Jan 1 1993
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Rab3A GTPase-activating protein-inhibiting activity of Rabphilin-3A, a putative Rab3A target protein'. Together they form a unique fingerprint.

  • Cite this

    Kishida, S., Shirataki, H., Sasaki, T., Kato, M., Kaibuchi, K., & Takai, Y. (1993). Rab3A GTPase-activating protein-inhibiting activity of Rabphilin-3A, a putative Rab3A target protein. Journal of Biological Chemistry, 268(30), 22259-22261.