Activation of exocytosis by GTP analogues in adrenal chromaffin cells revealed by patch‐clamp capacitance measurement

FEBS Letters

Burgoyne, Robert D.¹  Handel, Susan E.¹ 

[1] The Physiological Laboratory, PO Box 147, Liverpool L69 3BX, UK

关键词: Exocytosis;    Chromaffin cell;    GTP-binding protein;    Secretion;    Adrenal;    Calcium;    GTPγS;    guanosine 5′[γ-thio]triphosphate;    GppNHp;    guanosine 5′-[βγ-imido]triphosphate;    GDPβS;    guanosine 5′-[β-thio]diphosphate;    HEPES;    4-(2-hydroxyethyl)-1-piperazinethane sulfonic acid;    Ins(1;    4;    5)P3;    inositol(1;    4;    5)trisphosphate;    XTP;    xanthosine triphosphate;   

DOI  :  10.1016/0014-5793(94)00361-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The role of GTP-binding proteins in exocytosis in bovine adrenal chromaffin cells was examined using patch-clamp capacitance measurement. Internal dialysis with the non-hydrolysable GTP analogue guanosine 5′-[βγ-imido]triphosphate and xanthosine triphosphate (XTP) activated a capacitance increase. Exocytosis triggered by XTP was blocked by guanosine 5′-[β-thio]diphosphate (GDPβS) but Ca²⁺-induced exocytosis was unaffected. The capacitance increase due to XTP could not be explained by Ca²⁺ mobilisation since Ins(1,4,5)P₃ and caffeine did not mimic the response. Chromaffin cells appear to possess a Ca²⁺-independent pathway for exocytosis that involves GTP-binding proteins. The magnitude of the response to XTP suggested that GTP analogues stimulate both exocytosis and recruitment of secretory granules.

【 授权许可】

Unknown