Castellano A, Wei X, Birnbaumer L, Perez-Reyes E
Department of Molecular Physiology, Baylor College of Medicine, Houston, Texas 77030.
J Biol Chem. 1993 Feb 15;268(5):3450-5.
The skeletal muscle dihydropyridine receptor/Ca2+ channel consists of five distinct subunits (alpha 1, alpha 2 delta, beta 1, and gamma). Homologous alpha 1, alpha 2 delta, and beta 2 subunits are expressed in heart and brain. The present study reports the cloning and expression of a third beta subunit, beta 3, which is expressed predominantly in brain. Its open reading frame encodes a protein with 484 amino acids with a predicted molecular mass of 54,571 Da. Coexpression of beta 3 with a cardiac alpha 1 in Xenopus oocytes induces similar changes in Ca2+ channel activity as beta 1 and beta 2, that is, it increases peak currents, modulates the voltage dependence of activation, and accelerates activation. In addition, beta 3 accelerates the rate of inactivation at positive test potentials.
骨骼肌二氢吡啶受体/Ca2+通道由五个不同的亚基（α1、α2δ、β1和γ）组成。同源的α1、α2δ和β2亚基在心脏和大脑中表达。本研究报道了第三种β亚基β3的克隆和表达，其主要在大脑中表达。其开放阅读框编码一种含有484个氨基酸的蛋白质，预测分子量为54,571道尔顿。β3与心脏α1在非洲爪蟾卵母细胞中共表达，可诱导Ca2+通道活性发生与β1和β2类似的变化，即增加峰值电流、调节激活的电压依赖性并加速激活。此外，β3在正测试电位下加速失活速率。
