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Low molecular mass GTP‐binding proteins of adrenal chromaffin cells are present on the secretory granule
Author(s) -
Burgoyne Robert D.,
Morgan Alan
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80204-2
Subject(s) - granule (geology) , gtp' , biochemistry , adrenal medulla , chromaffin cell , exocytosis , chemistry , trypsin , polyacrylamide gel electrophoresis , blot , membrane , biology , enzyme , endocrinology , catecholamine , paleontology , gene
Adrenal medullary homogenates and chromaffin granule membranes were separated by SDS‐polyacrylamide gel electrophoresis and GTP‐binding proteins detected using [α‐ 32 P]GTP binding to nitrocellulose blots. Four GTP‐binding polypeptides of 24, 22, 20 and 18 kDa were routinely found in medullary homogenates and all were also found in isolated chromaffin granule membranes. The GTP‐binding polypeptides co‐sedimented with granule membrane markers following separation on sucrose gradients. On the basis of trypsin sensitivity and resistance to extraction, the GTP‐binding proteins appeared to be tightly bound to the cytoplasmic surface of the granules. One or more of the secretory granule GTP‐binding proteins could be involved in exocytosis in adrenal chromaffin cells.