Nishizaki T, Sumikawa K
Department of Psychobiology, University of California, Irvine 92717-4550.
Brain Res Mol Brain Res. 1994 Jul;24(1-4):341-5. doi: 10.1016/0169-328x(94)90148-1.
During development of neuromuscular junctions there is a switch in the expression of acetylcholine receptors (AChR) from an embryonic form (gamma-AChR) to an adult form (epsilon-AChR). Studies with gamma- and epsilon-AChRs expressed in Xenopus oocytes showed that the gamma to epsilon subunit switch accelerates rates of desensitization and increases Ca2+ permeability. Site-directed mutagenesis of the gamma and epsilon subunits suggests that these changes are regulated by cAMP-dependent phosphorylation on the epsilon subunit. These results suggest that the gamma to epsilon subunit switch could provide for a cAMP-dependent Ca2+ signalling pathway at the endplate.
在神经肌肉接头的发育过程中，乙酰胆碱受体（AChR）的表达会从胚胎形式（γ-AChR）转变为成年形式（ε-AChR）。对非洲爪蟾卵母细胞中表达的γ-和ε-AChR的研究表明，γ亚基向ε亚基的转变会加速脱敏速率并增加Ca2+通透性。γ亚基和ε亚基的定点诱变表明，这些变化受ε亚基上cAMP依赖性磷酸化的调节。这些结果表明，γ亚基向ε亚基的转变可能在终板处提供一条cAMP依赖性的Ca2+信号通路。
