Regulation of the phosphorylation of the inositol 1,4,5-trisphosphate receptor by protein kinase C
- Vermassen, Elke
- Fissore, Rafael A
- Nadif Kasri, Nael
- Vanderheyden, Veerle
- Callewaert, Geert
- Missiaen, Ludwig
- Parys, Jan
- De Smedt, Humbert
DOIAbstract
The various inositol 1,4,5-trisphosphate receptor (IP(3)R) isoforms are potential substrates for several protein kinases. We compared the in vitro phosphorylation of purified IP(3)R1 and IP(3)R3 by the catalytic subunit of protein kinase C (PKC). Phosphorylation of IP(3)R1 by PKC was about eight times stronger than that of IP(3)R3 under identical conditions. Protein kinase A strongly stimulated the PKC-induced phosphorylation of IP(3)R1. In contrast, Ca(2+) inhibited its phosphorylation (IC(50)<or=2microM) and this inhibition was further potentiated by calmodulin (CaM), while the Ca(2+)-independent CaM mutant CaM(1234) was ineffective. Ca(2+) and CaM, however, did not inhibit IP(3)R3 phosphorylation by PKC. Taken together, these findings sh...
Add to ORKG