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

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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

Fingerprint

rab3A GTP-Binding Protein
GTPase-Activating Proteins
Proteins
GTP Phosphohydrolases
Guanosine Triphosphate
Phospholipids
rabphilin-3A
Monomeric GTP-Binding Proteins
Neurotransmitter Agents

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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.

Rab3A GTPase-activating protein-inhibiting activity of Rabphilin-3A, a putative Rab3A target protein. / Kishida, S.; Shirataki, H.; Sasaki, T.; Kato, M.; Kaibuchi, K.; Takai, Y.

In: Journal of Biological Chemistry, Vol. 268, No. 30, 01.01.1993, p. 22259-22261.

Research output: Contribution to journalArticle

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, vol. 268, no. 30, pp. 22259-22261.
Kishida, S. ; Shirataki, H. ; Sasaki, T. ; Kato, M. ; Kaibuchi, K. ; Takai, Y. / Rab3A GTPase-activating protein-inhibiting activity of Rabphilin-3A, a putative Rab3A target protein. In: Journal of Biological Chemistry. 1993 ; Vol. 268, No. 30. pp. 22259-22261.
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