Naguro I, Nagao T, Adachi-Akahane S
Laboratory of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033, Tokyo, Japan.
FEBS Lett. 2001 Jan 26;489(1):87-91. doi: 10.1016/s0014-5793(01)02079-8.
Cardiac L-type Ca(2+) channel is facilitated by protein kinase A (PKA)-mediated phosphorylation. Here, we investigated the role of Ser(1901), a putative phosphorylation site in the carboxy-terminal of rat brain type-II alpha(1C) subunit (rbCII), in the PKA-mediated regulation. Forskolin (3 microM) enhanced Ca(2+) channel currents (I(Ca)) and shifted the activation curve to negative voltages, which were abolished by protein kinase inhibitor. Replacement of Ser(1901) of rbCII by Ala abolished the enhancement of I(Ca) by forskolin but not the shift of the activation curve. These results indicate that Ser(1901) is required for the PKA-mediated enhancement of I(Ca), and that the voltage-dependence of the activation of I(Ca) appears to be modulated via another PKA phosphorylation site.
心脏L型Ca(2+)通道受蛋白激酶A（PKA）介导的磷酸化作用促进。在此，我们研究了Ser(1901)（大鼠脑II型α(1C)亚基（rbCII）羧基末端的一个假定磷酸化位点）在PKA介导的调节中的作用。福斯高林（3 microM）增强了Ca(2+)通道电流（I(Ca)）并将激活曲线向负电压方向移动，而这被蛋白激酶抑制剂消除。将rbCII的Ser(1901)替换为丙氨酸消除了福斯高林对I(Ca)的增强作用，但未消除激活曲线的移动。这些结果表明，Ser(1901)是PKA介导的I(Ca)增强所必需的，并且I(Ca)激活的电压依赖性似乎是通过另一个PKA磷酸化位点调节的。
