Cyclic adenosine monophosphate dependent and independent phosphorylation of sarcolemma membrane proteins in perfused rat heart.
Cyclic adenosine monophosphate dependent and independent phosphorylation of sarcolemma membrane proteins in perfused rat heart.
复制标题
灌注大鼠心脏中肌膜膜蛋白的环单磷酸腺苷依赖性和非依赖性磷酸化。
作者：
D. Walsh;M. S. Clippinger;S. Sivaramakrishnan;T. E. McCullough
这项研究是为了进一步阐明肾上腺素通过蛋白磷酸化调节心脏功能的机制。从含有两种磷蛋白的冷冻夹闭灌流的大鼠心脏中分离出一种膜组分。这些蛋白质的分子量分别为36,000(A蛋白)和27,000(B蛋白)。A蛋白的磷酸化发生在心脏与无机[32P]磷酸盐的平衡过程中。B蛋白的磷酸化是对肾上腺素的反应。A和B蛋白与肌膜浓缩制剂中的两种磷酸蛋白明显相同。肌膜制剂中相当于A蛋白的蛋白质在体外被cAMP非依赖和cAMP依赖的蛋白激酶磷酸化。肌膜制剂中相当于B蛋白的蛋白质的磷酸化是由cAMP依赖的蛋白激酶催化的。因此，这些蛋白质在体内和体外的磷酸化模式是兼容的。B蛋白的磷酸化已经在体外被证明可以调节钙的运输(Will，H.，et al.(1973)Acta Biol.地中海医院。杰尔。31，45-52)，但灌流心脏对肾上腺素的反应与儿茶酚胺诱导的变力作用并不明显地协调。
This study was initiated in order to elaborate further on the mechanism by which epinephrine modulates cardiac function via protein phosphorylation. A membrane fraction has been isolated from freeze-clamped perfused rat heart that contains two phosphoproteins. These proteins have molecular weights of 36,000 (A protein) and 27,000 (B protein). The phosphorylation of the A protein occurs during the equilibration of the heart with inorganic [32P]phosphate. The phosphorylation of the B protein occurs in response to epinephrine. The A and B proteins are apparently identical with two phosphoproteins in enriched preparations of sarcolemma. The protein of the sarcolemma preparation equivalent to the A protein is phosphorylated in vitro by both cAMP-independent and cAMP-dependent protein kinases. The phosphorylation of the protein of the sarcolemma preparation equivalent to the B protein is catalyzed by the cAMP-dependent protein kinase. Thus the patterns of phosphorylation of these proteins in vivo and in vitro are compatible. The phosphorylation of the B protein has been documented in vitro to modulate calcium transport (Will, H., et al. (1973) Acta Biol. Med. Ger. 31, 45-52), but the response to epinephrine in the perfused heart is not apparently coordinated with the catecholamine-induced inotropic effect.