Modulation of phospholipase A2 activity in zymogen granule membranes by GTP[S]; evidence for GTP-binding protein regulation.
In membranes associated with purified pancreatic zymogen granules, GTP[S] elicited a concentration-dependent activation of phospholipase A2 (PLA2), which was converted to inhibition in the presence of added Ca2+. The GTP-binding protein inhibitor GDP[S] blocked both the stimulatory and inhibitory actions of GTP[S]. We conclude that in zymogen granule membranes GTP-binding proteins exert a dual regulation of PLA2 activity.
Rubin
R P
RP
Department of Pharmacology & Therapeutics, State University of New York, Buffalo 14214.
Withiam-Leitch
M
M
Laychock
S G
SG
D000818:Animals; D003594:Cytoplasmic Granules / Q000201:enzymology*; D004792:Enzyme Precursors / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000201:enzymology*; D007700:Kinetics; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2
D004792:Enzyme Precursors; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D010741:Phospholipases A; D054467:Phospholipases A2; D019204:GTP-Binding Proteins