Mastoparan and Rab3AL peptide potentiation of calcium‐independent secretory activity in rat melanotrophs is inhibited by GDPβS

FEBS Letters

Zorec, R²  Mason, W.T¹  Rupnik, M²  Law, G.J¹ 

[1] The Babraham Institute, Babraham, Cambridge, CB2 4AT, UK;Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, School of Medicine, P.O. Box 2211, 1001 Ljubljana, Slovenia

关键词: Rat melanotroph;    Membrane capacitance;    GTP-binding protein;    Exocytosis;    Rab3 protein;    Mastoparan;   

DOI  :  10.1016/S0014-5793(97)00731-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The whole-cell patch-clamp membrane capacitance measurement was used to monitor secretory activity in rat melanotrophs, while rab3AL, putative effector domain peptides of Rab3 small GTPases (20–30 kDa), were introduced into cytosol. In melanotrophs dialyzed with calcium free solutions membrane capacitance tends to decrease slightly. This decrease is further potentiated with GDPβS (500 μM). We found that rab3AL (100 μM) stimulated secretory activity in the absence of calcium. The rab3AL response was qualitatively comparable to the response to mastoparan (1 μM), an activator of certain heterotrimeric GTP-binding proteins. Interestingly, inclusion of GDPβS (500 μM) resulted in a blockade of both rab3AL and mastoparan induced responses. We conclude that rab3AL and mastoparan induce calcium-independent stimulation of secretory activity in rat melanotrophs by activation of a downstream heterotrimeric GTP-binding protein.

【 授权许可】

Unknown