Evidence for involvement of guanine nucleotide-binding regulatory proteins in the activation of phospholipases by hormones.
Guanine nucleotide-binding regulatory proteins similar to Gs and Gi may be involved in the activation of phospholipases C and A2 by hormones and other ligands. The binding of hormones to receptors that activate phospholipase C is decreased by guanine nucleotides and these hormones also stimulate a high-affinity GTPase activity in cell membranes. Effects of hormones on phospholipase C activity in cell-free preparations are dependent on the presence of guanine nucleotides. In addition, fluoride and nonhydrolyzable GTP analogs activate phospholipases in a manner that can be blocked by GDP beta S. The putative guanine nucleotide-binding regulatory protein that appears to be involved in activation of phospholipase C is sensitive to pertussis toxin in some cells but not in others.
Fain
J N
JN
Department of Biochemistry, College of Medicine, University of Tennesse, Memphis 38163.
Wallace
M A
MA
Wojcikiewicz
R J
RJ
D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000502:physiology*; D006150:Guanine Nucleotides / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology*; D006801:Humans; D010716:Phosphatidylinositols / Q000378:metabolism; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism
D006150:Guanine Nucleotides; D006728:Hormones; D010716:Phosphatidylinositols; D010740:Phospholipases; D010741:Phospholipases A; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins