PHOSPHORYLATION OF A BOVINE CARDIAC ACTIN COMPLEX
PHOSPHORYLATION OF A BOVINE CARDIAC ACTIN COMPLEX
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DOI：
10.1152/ajpcell.1979.236.1.c41
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发表时间：
1979-01-01
影响因子：
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通讯作者：
BAILIN, G
中科院分区：
文献类型：
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作者：
BAILIN, G
牛心脏肌动蛋白-原肌球蛋白-肌钙蛋白复合物在[γ- 32 P]ATP、Mg 2+、环[c]AMP和牛心脏c-AMP依赖性蛋白激酶。大约81%的[32 P]磷酸盐被确定为磷酸丝氨酸和磷酸苏氨酸。凝胶电泳显示，55%的[32 P]磷酸盐与肌钙蛋白（Tn-I）的抑制组分相关，24%与肌动蛋白复合物中类似于肌钙蛋白的原肌球蛋白结合组分的蛋白质相关。当Ca 2+从0.1 μ M增加到50 μ M时，肌动蛋白复合物中Tn-I的磷酸化被抑制30%，但其他成分的磷酸化不受Ca 2+浓度增加的影响。用[32]磷酸化的心脏肌动蛋白复合物和心肌肌球蛋白制成的重组肌动蛋白的ATP酶活性的半最大Ca激活被转移到Ca 2+值，高于用非磷酸化的肌动蛋白复合物制成的肌动蛋白。
A bovine cardiac actin-tropomyosin-troponin complex was phosphorylated in the presence of [.gamma.-32P]ATP, Mg2+, cyclic[c]AMP, and bovine cardiac c-AMP-dependent protein kinase. Approximately 81% of the [32P]phosphate incorporated was identified as phosphoserine and phosphothreonine. Gel electrophoresis showed that 55% of the [32P]phosphate was associated with the inhibitory component of troponin (Tn-I) and 24% with a protein resembling the tropomyosin-binding component of troponin in the actin complex, respectively. Phosphorylation of Tn-I in the actin complex was inhibited 30% when Ca2+ was increased from 0.1 to 50 .mu.M, but phosphorylation of other components was not affected by increasing Ca2+ concentration. Half-maximal Ca activation of the ATPase activity of reconstituted actomyosins made with the [32]phosphorylated cardiac actin complex and cardiac myosin was shifted to Ca2+ values higher than those of actomyosins made with the nonphosphorylated actin complex.