The α Subunit of the GTP Binding Protein Gk Opens Atrial Potassium Channels
Abstract
Guanine nucleotide binding (G) proteins (subunit composition α β γ ) dissociate on activation with guanosine triphosphate (GTP) analogs and magnesium to give α -guanine nucleotide complexes and free β γ subunits. Whether the opening of potassium channels by the recently described Gk in isolated membrane patches from mammalian atrial myocytes was mediated by the α k subunit or β γ dimer was tested. The α k subunit was found to be active, while the β γ dimer was inactive in stimulating potassium channel activity. Thus, Gk resembles Gs, the stimulatory regulatory component of adenylyl cyclase, and transducin, the regulatory component of the visual system, in that it regulates its effector function--the activity of the ligand-gated potassium channel--through its guanine nucleotide binding subunit.
- Publication:
-
Science
- Pub Date:
- April 1987
- DOI:
- 10.1126/science.2436299
- Bibcode:
- 1987Sci...236..442C