Possible role of H+—alkali cation countertransport in secretary granule swelling during exocytosis

FEBS Letters

Grinstein, Sergio¹  Vander Meulen, J.¹  Furuya, W.¹ 

[1] Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada

关键词: Exocytosis;    H+ transport;    Countertransport;    Proton gradient;    Secretory granule;    Secretion;    Osmotic swelling;   

DOI  :  10.1016/0014-5793(82)81230-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Studies in model systems, as well as observations in intact cells, suggest that osmotic swelling of secretory granules is an essential step in exocytosis. A model is proposed whereby the low pH recorded in most secretory organelles could provide the driving force for granule swelling. The model assumes that during stimulation an exchange of H⁺ for alkali cations is triggered across the granule membrane. The outgoing H⁺ are rapidly replaced by the internal buffering capacity with a concomitant osmotic gain. The exchange is independent of anions and could be triggered by cytoplasmic Ca²⁺. The H⁺-pump is responsible for the ΔpH but independent of the exchange mechanism.

【 授权许可】

Unknown