| Autor: |
Grigory Krapivinsky, Luba Krapivinsky, Pramesh Kovoor, Susanne Arnold, Igor Medina, David E. Clapham |
| Rok vydání: |
2000 |
| Předmět: |
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| Zdroj: |
Journal of Biological Chemistry. 275:29709-29716 |
| ISSN: |
0021-9258 |
| DOI: |
10.1074/jbc.m004989200 |
| Popis: |
G protein-gated inwardly rectifying potassium (GIRK) channels are a family of K+-selective ion channels that slow the firing rate of neurons and cardiac myocytes. GIRK channels are directly bound and activated by the G protein Gβγ subunit. As heterotetramers, they comprise the GIRK1 and the GIRK2, -3, or -4 subunits. Here we show that GIRK1 but not the GIRK4 subunit is phosphorylated when heterologously expressed. We found also that phosphatase PP2A dephosphorylation of a protein in the excised patch abrogates channel activation by Gβγ. Experiments with the truncated molecule demonstrated that the GIRK1 C-terminal is critical for both channel phosphorylation and channel regulation by protein phosphorylation, but the critical phosphorylation sites were not located on the C terminus. These data provide evidence for a novel switch mechanism in which protein phosphorylation enables Gβγ gating of the channel complex. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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