Szyszka R, Boguszewska A, Grankowski N, Ballesta J P
Department of Molecular Biology, Maria Curie-Skłodowska University, Lublin, Poland.
Acta Biochim Pol. 1995;42(3):357-62.
The native 80S ribosomes isolated from Saccharomyces cerevisiae (strain W303) cells was phosphorylated by two endogenous protein kinases: multifunctional casein kinase-2 (CK-2) and specific 60S kinase. Three acidic proteins within the 60S ribosomal subunit: YP1 beta, YP1 beta' and YP2 alpha are phosphorylated by both kinases. The other two proteins: YP1 alpha and YP2 beta are predominantly phosphorylated by CK-2 but not by 60S kinase. This was confirmed in the experiment with the recombinant protein, YP2 beta, as a substrate, which is practically not phosphorylated by specific 60S kinase. These results together with the previous data based on the target amino-acid sequences suggest that, in addition to the multifunctional casein kinase-2 and specific 60S kinase, there exist probably other protein kinase(s) which phosphorylate the ribosomal acidic proteins in the cell.
从酿酒酵母（W303菌株）细胞中分离出的天然80S核糖体被两种内源性蛋白激酶磷酸化：多功能酪蛋白激酶-2（CK-2）和特异性60S激酶。60S核糖体亚基中的三种酸性蛋白：YP1β、YP1β'和YP2α被这两种激酶磷酸化。另外两种蛋白：YP1α和YP2β主要被CK-2磷酸化，而不被60S激酶磷酸化。以重组蛋白YP2β为底物的实验证实了这一点，该重组蛋白实际上不被特异性60S激酶磷酸化。这些结果与基于目标氨基酸序列的先前数据一起表明，除了多功能酪蛋白激酶-2和特异性60S激酶外，细胞中可能还存在其他使核糖体酸性蛋白磷酸化的蛋白激酶。
