期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：20
页码：9454-9458
DOI：10.1073/pnas.89.20.9454
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Casein kinase I (CKI) is a class of protein kinases ubiquitous to all eukaryotic cells. Recently, cDNA clones encoding several bovine CKI isoforms have been sequenced that show high sequence identity to the HRR25 gene product of the budding yeast Saccharomyces cerevisiae; HRR25 is required for normal cellular growth, nuclear segregation, DNA repair, and meiosis. We have raised polyclonal antibodies to a human erythroid 34-kDa CKI and have sequenced a portion of this kinase. The amino acid sequence identifies the CKI as the alpha-CKI isoform, which is 62% identical to the HRR25 protein kinase. By use of immunofluorescence, the alpha-CKI has been localized to vesicular cytosolic structures and to the centrosome in interphase cells. As cells progress into mitosis, centrospheric staining increases and, in mitosis, alpha-CKI associates with kinetochore fibers. This localization suggests that alpha-CKI, like HRR25, plays a role in the segregation of chromosomes during mitosis and may be cell cycle-regulated both in humans and in yeast.
