Positive- and negative-regulation of Ca2+ entry through ACh receptor channels by phosphorylation.
During development of mammalian neuromuscular junctions, the expression of ACh receptors (AChRs) switches from an embryonic form to an adult form, which provides a higher Ca2+ permeable channel. The lack of this switch can prevent normal development of neuromuscular junctions. In non-mammalian species, however, the switch appears not to occur. The results of the present study show that Ca2+ entry through non-mammalian AChR channels was controlled by differential phosphorylation rather than a subunit switch. This finding provides support for the hypothesis that localized Ca2+ influx through AChR channels has a critical role in the formation and maintenance of neuromuscular junctions.
Nishizaki
T
T
Department of Physiology, Kobe University School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650, Japan.
Matsuoka
T
T
Sumikawa
K
K
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002645:Chickens; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D009469:Neuromuscular Junction / Q000502:physiology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000378:metabolism*; D014101:Torpedo
D011950:Receptors, Cholinergic; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D002118:Calcium