Phosphorylation of the rat Ins(1,4,5)P₃ receptor at T930 within the coupling domain decreases its affinity to Ins(1,4,5)P₃.
Channels (Austin) 2012;
6:379-84. [PMID:
22878752 PMCID:
PMC3508777 DOI:
10.4161/chan.21170]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Ins(1,4,5)P3 receptor acts as a central hub for Ca2+ signaling by integrating multiple signaling modalities into Ca2+ release from intracellular stores downstream of G-protein and tyrosine kinase-coupled receptor stimulation. As such, the Ins(1,4,5)P3 receptor plays fundamental roles in cellular physiology. The regulation of the Ins(1,4,5)P3 receptor is complex and involves protein-protein interactions, post-translational modifications, allosteric modulation, and regulation of its sub-cellular distribution. Phosphorylation has been implicated in the sensitization of Ins(1,4,5)P3-dependent Ca2+ release observed during oocyte maturation. Here we investigate the role of phosphorylation at T-930, a residue phosphorylated specifically during meiosis. We show that a phosphomimetic mutation at T-930 of the rat Ins(1,4,5)P3 receptor results in decreased Ins(1,4,5)P3-dependent Ca2+ release and lowers the Ins(1,4,5)P3 binding affinity of the receptor. These data, coupled to the sensitization of Ins(1,4,5)P3-dependent Ca2+ release during meiosis, argue that phosphorylation within the coupling domain of the Ins(1,4,5)P3 receptor acts in a combinatorial fashion to regulate Ins(1,4,5)P3 receptor function.
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