Inhibition of pituitary hormone exocytosis by a synthetic peptide related to the rab effector domain

FEBS Letters

Roeske, R.W.²  Davidson, J.S.¹  Millar, R.P.¹  Eales, A.¹ 

[1] Regulatory Peptides Research Unit, Department of Chemical Pathology, University of Cape Town Medical School, Cape Town 7925, South Africa;Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, USA

关键词: Exocytosis;    Rab;    GTP-binding protein;    Secretion;    Pituitary;    Luteinizing hormone;    Growth hormone;   

DOI  :  10.1016/0014-5793(93)81794-Z

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

GTP-binding proteins of the rab family are believed to function at several steps in intracellular vesicular transport. We examined the effects of a rab-related peptide in permeabilized pituitary cells, in which exocytosis can be triggered by distinct Ca²⁺-dependent or Ca²⁺-independent pathways. We report that a synthetic peptide of 18 amino acids related to the rab effector domain, rab3AL(30–47) inhibited luteinizing hormone (LH) and growth hormone (GH) exocytosis triggered by either pathway. Ca²⁺-stimulated LH and GH release were inhibited by more than 80% and 50%, respectively, by 100 μM peptide. The peptide (100 μM) also inhibited LH and GH exocytosis stimulated by phorbol myristate acetate plus cAMP by more than 45% and 80%, respectively. The effect was sequence-specific since a second peptide, lacking the first 3 amino acids but otherwise identical failed to inhibit exocytosis. These results suggest that a protein of the rab family is involved in regulated pituitary hormone exocytosis, and they identify 3 amino acids of the putative rab effector domain which may be functionally important in exocytosis.

【 授权许可】

Unknown