Regulation of brain phosphatidylinositol-4-phosphate kinase by GTP analogues. A potential role for guanine nucleotide regulatory proteins.
Incorporation of 32P from [gamma-32P]ATP into phosphatidylinositol 4,5-bisphosphate (PIP2) in membranes isolated from rat brain was enhanced in a concentration-dependent manner by the GTP analogue guanosine 5'-O-(thio)triphosphate (GTP gamma S). In contrast, neither the labeling of phosphatidylinositol 4-phosphate in the same membranes nor PIP kinase activity in the soluble fraction were stimulated by GTP gamma S. Synthesis of [32P]PIP2 was not stimulated by GTP, GDP, GMP, or ATP; however, the stimulatory effects of GTP gamma S were antagonized by GTP, GDP, and guanosine 5'-O-thiodiphosphate (GDP beta S). The nucleotide-stimulated labeling of PIP2 was not due to protection of [gamma-32P] ATP from hydrolysis, activation of PIP2 hydrolysis by phospholipase C, or inhibition of PIP2 hydrolysis by its phosphomonoesterase. Therefore, phosphatidylinositol 4-phosphate kinase activity in brain membranes may be regulated by a guanine nucleotide regulatory protein. This system may enhance the resynthesis of PIP2 following receptor-mediated activation of phospholipase C.
Smith
C D
CD
Division of Cell Biology, Burroughs Wellcome Co., Research Triangle Park, North Carolina 27709.
Chang
K J
KJ
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006157:Guanosine Monophosphate / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor); D051381:Rats; D013873:Thionucleotides / Q000494:pharmacology
D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D013873:Thionucleotides; C037178:phosphatidylinositol 4-phosphate; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C023427:guanosine 5'-O-(2-thiodiphosphate); D006157:Guanosine Monophosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase; D019204:GTP-Binding Proteins; D008274:Magnesium