Cloning of a mouse Rabphilin-3A expressed in hormone-secreting cells.
Rab3A, a ras p21-related small GTP-binding protein, is implicated in the exocytosis of neurotransmitters. Recently, Rabphilin-3A, a putative target protein for Rab3A, was identified and its cDNA has been cloned from bovine brain. In this study, we isolated a cDNA encoding a mouse Rabphilin-3A homolog from the insulin-secreting cell line, MIN6. Mouse Rabphilin-3A is a protein of 681 amino acids exhibiting overall 88.5% identity with bovine Rabphilin-3A. The amino acid identity between mouse and bovine Rabphilin-3A is highest in their carboxyl-terminal halves (97.8% identity) and amino-termini (93.0% identity), which contain the region of the two internal repeats homologous to the regulatory domain (C2 domain) of protein kinase C and the putative Rab3A-binding region, respectively. RNA blot analysis revealed that Rabphilin-3A mRNA is expressed in endocrine and hormone-secreting clonal cells, including rat adrenal glands, MIN6, the hamster insulin-secreting cell line, HIT-T15, and the rat catecholamine-secreting cell line, PC12, as well as rat brain. These results suggest that Rabphilin-3A might be involved in the exocytosis of secretory vesicles in hormone-secreting cells as well as in neurons.
Inagaki
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N
Division of Molecular Medicine, Chiba University School of Medicine.
Mizuta
M
M
Seino
S
S
D048868:Adaptor Proteins, Signal Transducing; D000305:Adrenal Cortex Hormones / Q000378:metabolism; D000311:Adrenal Glands / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D002417:Cattle; D002460:Cell Line / Q000737:chemistry; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics* / Q000302:isolation & purification*; D019204:GTP-Binding Proteins / Q000235:genetics*; D015698:Genomic Library; D006728:Hormones / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D016716:PC12 Cells / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats; D017386:Sequence Homology, Amino Acid; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins; D000097624:Rabphilin-3A
D048868:Adaptor Proteins, Signal Transducing; D000305:Adrenal Cortex Hormones; D018076:DNA, Complementary; D019204:GTP-Binding Proteins; D006728:Hormones; D007328:Insulin; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins; D000097624:Rabphilin-3A