Open AccessRole of aquaporins and regulation of secretory vesicle volume in cell secretion
Author(s) -
Sugiya H.,
MatsukiFukushima M.,
Hashimoto S.
Publication year - 2008
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2008.00239.x
Subject(s) - secretory vesicle , secretion , microbiology and biotechnology , secretory pathway , secretory protein , granule (geology) , golgi apparatus , endoplasmic reticulum , biology , vesicle , aquaporin , intracellular , vacuole , exocytosis , biochemistry , chemistry , cytoplasm , membrane , paleontology
• Introduction • Role of AQPs in cell secretion – Role of AQPs in secretory granule swelling – Role of AQPs in ion permeation• ConclusionsAbstract In exocrine glands, secretory proteins synthesized in the rough endoplasmic reticulum (RER) exhibit vectorial transport from ER through a succession of membrane‐bounded components such as Golgi complex, condensing vacuoles and secretory granules. The secretory granules migrate to particular locations within the cell close to the apical membrane prior to the release of their contents into the acinar lumen. Currently, to release intragranular contents, secretory granules have been demonstrated to transiently dock and fuse at ‘porosome’, a permanent cup‐shaped structures at the cell membranes. Then swelling of secretory granules occurs to allow explusion of intragranular contents. In this process, water and ion fluxes in the granule membrane appear to contribute to maintain secretory granule integrity and morphology via osmoregulation in secretory granules. Aquaporins (AQPs) are a family of small, hydrophobic, integral membrane proteins, which function as channels to permeate water and small solutes. The AQPs reside constitutively at the plasma membrane in most cell types. However, recent studies have demonstrated that the AQPs are present in secretory granules in exocrine glands, synaptic vesicles and intracellular vesicles in liver and kidney, implying that AQPs in secretory granules and vesicles are involved in their volume regulation. This paper reviews the possible role of AQPs on secretory granules, especially in exocrine glands, in secretory function.