Vancura A, Sessler A, Leichus B, Kuret J
Cold Spring Harbor Laboratory, New York 11724-2220.
J Biol Chem. 1994 Jul 29;269(30):19271-8.
The subcellular distribution of three casein kinase I (CK1) homologs, encoded by the YCK1, YCK2, and HRR25 genes, has been determined in budding yeast through a combination of subcellular fractionation and immunofluorescence methods. Both Yck proteins are tightly associated with the plasma membrane or underlying cytoskeleton and require both high-salt and nonionic detergent for extraction. Association is mediated primarily by the prenylation motif found at the C terminus of both Yck proteins. In contrast, the third CK1 homolog, Hrr25p, is found predominantly in the nucleus and only partially in the plasma membrane. Despite partial colocalization with the Yck proteins, Hrr25p is unable to rescue the yck1 delta yck2 delta phenotype. However, a chimeric kinase containing the N-terminal kinase domain of Hrr25p and the C-terminal region of Yck2p contains full Yck activity in vivo. These data suggest that members of the casein kinase I family have distinct but partially overlapping distributions in the cell that are mediated by their unique C-terminal regions.
通过亚细胞分级分离和免疫荧光方法相结合，已在芽殖酵母中确定了由YCK1、YCK2和HRR25基因编码的三种酪蛋白激酶I（CK1）同源物的亚细胞分布。两种Yck蛋白都与质膜或其下方的细胞骨架紧密相关，并且需要高盐和非离子去污剂才能提取。这种结合主要由两种Yck蛋白C末端的异戊二烯化基序介导。相比之下，第三种CK1同源物Hrr25p主要存在于细胞核中，仅部分存在于质膜中。尽管与Yck蛋白部分共定位，但Hrr25p无法挽救yck1δyck2δ表型。然而，一种包含Hrr25p的N末端激酶结构域和Yck2p的C末端区域的嵌合激酶在体内具有完整的Yck活性。这些数据表明，酪蛋白激酶I家族成员在细胞中具有不同但部分重叠的分布，这是由它们独特的C末端区域介导的。
