Rabphilin-3A, a putative target protein for smg p25A/rab3A p25 small GTP-binding protein related to synaptotagmin.
Open Access
- 1 April 1993
- journal article
- research article
- Published by Taylor & Francis in Molecular and Cellular Biology
- Vol. 13 (4) , 2061-2068
- https://doi.org/10.1128/mcb.13.4.2061
Abstract
In a previous study (H. Shirataki, K. Kaibuchi, T. Yamaguchi, K. Wada, H. Horiuchi, and Y. Takai, J. Biol. Chem. 267:10946-10949, 1992), we highly purified from bovine brain crude membranes the putative target protein for smg p25A/rab3A p25, a ras p21-related small GTP-binding protein implicated in neurotransmitter release. In this study, we have isolated and sequenced the cDNA of this protein from a bovine brain cDNA library. The cDNA had an open reading frame encoding a protein of 704 amino acids with a calculated M(r) of 77,976. We tentatively refer to this protein as rabphilin-3A. Structural analysis of rabphilin-3A revealed the existence of two copies of an internal repeat that were homologous to the C2 domain of protein kinase C as described for synaptotagmin, which is known to be localized in the membrane of the synaptic vesicle and to bind to membrane phospholipid in a Ca(2+)-dependent manner. The isolated cDNA was expressed in COS7 cells, and the encoded protein was recognized with an anti-rabphilin-3A polyclonal antibody and was identical in size with rabphilin-3A purified from bovine brain by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Moreover, both rabphilin-3A purified from bovine brain and recombinant rabphilin-3A made a complex with the GTP gamma S-bound form of rab3A p25 but not with the GDP-bound form of rab3A p25. Immunoblot and Northern (RNA) blot analyses showed that rabphilin-3A was highly expressed in bovine and rat brains. These results indicate that rabphilin-3A is a novel protein that has C2 domains and selectively interacts with the GTP-bound form of rab3A p25.Keywords
This publication has 54 references indexed in Scilit:
- Localization of smg p25A/rab3A p25, a small gtp-binding protein, at the active zone of the rat neuromuscular junctionBiochemical and Biophysical Research Communications, 1992
- Phospholipid binding by a synaptic vesicle protein homologous to the regulatory region of protein kinase CNature, 1990
- rab3 is a small GTP-binding protein exclusively localized to synaptic vesicles.Proceedings of the National Academy of Sciences, 1990
- Purification and characterization from bovine brain cytosol of a protein that inhibits the dissociation of GDP from and the subsequent binding of GTP to smg p25A, a ras p21-like GTP-binding protein.Journal of Biological Chemistry, 1990
- Activation of the Serum Response Element and 12-O-Tetradecanoylphorbol-13-Acetate Response Element by the Activated c-raf-1 Protein in a Manner Independent of Protein Kinase CJournal of Biological Chemistry, 1989
- Tissue distribution of smg p25A, a ras p21-like GTP-binding protein, studied by use of a specific monoclonal antibodyBiochemical and Biophysical Research Communications, 1989
- Tissue-specific expression of a novel GTP-binding protein (smg p25A) mRNA and its increase by nerve growth factor and cyclic AMP in rat pheochromocytoma PC-12 cellsBiochemical and Biophysical Research Communications, 1989
- Nucleotide and deduced amino acid sequences of a GTP-binding protein family with molecular weights of 25,000 from bovine brain.Journal of Biological Chemistry, 1988
- The molecular heterogeneity of protein kinase C and its implications for cellular regulationNature, 1988
- Endocrine secretory granules and neuronal synaptic vesicles have three integral membrane proteins in common.The Journal of cell biology, 1988