Autophosphorylation of inositol 1,4,5-trisphosphate receptors.
Inositol 1,4,5-trisphosphate (IP3) releases internal stores of calcium by binding to a specific membrane receptor which includes both the IP3 recognition site as well as the associated calcium channel. The IP3 receptor is regulated by ATP, calcium, and phosphorylation by protein kinase A, protein kinase C, and calcium/calmodulin-dependent protein kinase II. Its cDNA sequence predicts at least two consensus sequences where nucleotides might bind, and direct binding of ATP to the IP3 receptor has been demonstrated. In the present study, we demonstrate autophosphorylation of the purified and reconstituted IP3 receptor on serine and find serine protein kinase activity of the IP3 receptor toward a specific peptide substrate. Several independent purification procedures do not separate the IP3 receptor protein from the phosphorylating activity, and many different protein kinase activators and inhibitors do not identify protein kinases as contaminants. Also, renaturation experiments reveal autophosphorylation of the monomeric receptor on polyvinylidene difluoride membranes.
Ferris
C D
CD
Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Cameron
A M
AM
Bredt
D S
DS
Huganir
R L
RL
Snyder
S H
SH
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007295:Inositol Phosphates / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D013379:Substrate Specificity
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007295:Inositol Phosphates; D009842:Oligopeptides; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; C037642:kemptide; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D002118:Calcium