Autophosphorylation of rhodopsin kinase from retinal rod outer segments.
Autophosphorylation of rhodopsin kinase from retinal rod outer segments.
复制标题
视网膜视杆外节视紫红质激酶的自磷酸化。
DOI：
10.1021/bi00257a009
复制
发表时间：
1982
期刊：
影响因子：
2.9
通讯作者：
R. Lolley
中科院分区：
文献类型：
--
作者：
R. H. Lee;B. Brown;R. Lolley
视紫红质激酶已被鉴定为一种 68K 蛋白质，从暗适应视杆外节（暗提取物）中提取比从照明视杆外节（光提取物）中提取更容易。我们观察到，68K 蛋白被牛视杆外节暗提取物或光提取物的内源蛋白激酶磷酸化，并且暗提取物中掺入的放射性 (32P) 量比光提取物中的含量更高。 68K 蛋白的磷酸化既不受环核苷酸刺激，也不受磷酸化反应的光照或黑暗条件的影响。在单独的蔗糖密度梯度上同时离心浅色和深色提取物，揭示了与浅色提取物相比，深色提取物中具有内源性视紫红质激酶活性的68K磷蛋白共沉积物以及更高的32P掺入和更高的视紫红质激酶活性。这些发现强烈表明 68K 磷蛋白和视紫红质激酶是相同的，并且视紫红质激酶经历自磷酸化。
Rhodopsin kinase has been identified as a 68K protein that is more readily extracted from dark-adapted rod outer segments (dark-extract) than from illuminated rod outer segments (light-extract). We observed that a 68K protein is phosphorylated by endogenous protein kinase of dark- or light-extract of bovine rod outer segments and that the amount of incorporated radioactivity (32P) was greater in the dark-than in the light-extract. Phosphorylation of the 68K protein is neither stimulated by cyclic nucleotides nor affected by the light or dark conditions of the phosphorylation reaction. Light-and dark-extracts were centrifuged simultaneously on individual sucrose density gradients revealing that the 68K phosphoprotein cosediments with endogenous rhodopsin kinase activity and that both greater 32P incorporation and higher rhodopsin kinase activity are found in dark-extract as compared to light-extract. These findings suggest strongly that the 68K phosphoprotein and rhodopsin kinase are identical and that rhodopsin kinase undergoes autophosphorylation.