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- Title
Regulation of Ca2+ channel expression at the cell surface by the small G-protein kir/Gem.
- Authors
Béguin, P; Nagashima, K; Gonoi, T; Shibasaki, T; Takahashi, K; Kashima, Y; Ozaki, N; Geering, K; Iwanaga, T; Seino, S
- Abstract
Voltage-dependent calcium (Ca2+) channels are involved in many specialized cellular functions, and are controlled by intracellular signals such as heterotrimeric G-proteins, protein kinases and calmodulin (CaM). However, the direct role of small G-proteins in the regulation of Ca2+ channels is unclear. We report here that the GTP-bound form of kir/Gem, identified originally as a Ras-related small G-protein that binds CaM, inhibits high-voltage-activated Ca2+ channel activities by interacting directly with the beta-subunit. The reduced channel activities are due to a decrease in alpha1-subunit expression at the plasma membrane. The binding of Ca2+/CaM to kir/Gem is required for this inhibitory effect by promoting the cytoplasmic localization of kir/Gem. Inhibition of L-type Ca2+ channels by kir/Gem prevents Ca2+-triggered exocytosis in hormone-secreting cells. We propose that the small G-protein kir/Gem, interacting with beta-subunits, regulates Ca2+ channel expression at the cell surface.
- Publication
Nature, 2001, Vol 411, Issue 6838, p701
- ISSN
0028-0836
- Publication type
Journal Article
- DOI
10.1038/35079621