G-protein regulation of capacitative calcium entry may be mediated by protein kinases A and C in Xenopus oocytes.
Inositol 2,4,5-trisphosphate irreversibly activated capacitative calcium entry in Xenopus oocytes, whereas guanosine thiotriphosphate (GTP[S]) and AIF4- only activated capacitative calcium entry transiently. Both GTP[S] and AIF4- inhibited capacitative calcium entry activated by thapsigargin pretreatment, but guanosine thiodiphosphate (GDP[S]), inositol 2,4,5-trisphosphate and dibutyryl cyclic GMP did not affect capacitative calcium entry. This suggests the involvement of heterotrimeric GTP-binding proteins in the regulation of capacitative calcium entry. Activation of protein kinase C or cyclic-AMP-dependent protein kinase had profound effects on capacitative calcium entry, which were consistent with the hypothesis that the effects of GTP[S] and AIF4- on capacitative calcium entry may be mediated via heterotrimeric GTP-binding protein stimulation of kinases. Further evidence for this hypothesis was derived from the result that the effects of GTP[S] on calcium entry could be inhibited by the application of the protein kinase inhibitor staurosporine.
Petersen
C C
CC
Babraham Institute Laboratory of Molecular Signalling, Department of Zoology, University of Cambridge, U.K.
Berridge
M J
MJ
D000262:Adenylyl Cyclases / Q000378:metabolism; D017607:Aluminum Compounds / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D018118:Chloride Channels / Q000502:physiology; D005576:Colforsin / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology; D004789:Enzyme Activation; D005260:Female; D005459:Fluorides / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D007295:Inositol Phosphates / Q000494:pharmacology; D009865:Oocytes / Q000378:metabolism / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism; D014982:Xenopus laevis
D017607:Aluminum Compounds; D018118:Chloride Channels; D007295:Inositol Phosphates; D005576:Colforsin; D003995:Dibutyryl Cyclic GMP; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D015544:Inositol 1,4,5-Trisphosphate; C062616:inositol 2,4,5-trisphosphate; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D013755:Tetradecanoylphorbol Acetate; D005459:Fluorides; D002118:Calcium; C032311:aluminum fluoride