Stirling D A, Stark M J
Department of Biochemistry, University of Dundee, United Kingdom.
Biochem Biophys Res Commun. 1996 May 15;222(2):236-42. doi: 10.1006/bbrc.1996.0728.
The 110 kDa component of the yeast spindle pole body (SPB) encoded by the SPC110/NUF1 gene is an essential protein which is important for the generation of a functional mitotic spindle in the yeast Saccharomyces cerevisiae. Spc110p exists in a number of forms which differ in mobility upon separation by SDS-polyacrylamide gel electrophoresis. We show that this heterogeneity is due to differential phosphorylation on serine or threonine residues and that Spc110p phosphorylation varies throughout the cell cycle. Specifically, the phosphorylated form Spc110p appears as cells progress from S-phase and is coincident with the presence of preanaphase mitotic spindles. Thus phosphorylation of Spc110p occurs at the stage in the cell cycle where SPBs acquire the competence to organize a mitotic spindle and could therefore represent an important regulatory event.
由SPC110/NUF1基因编码的酵母纺锤体极体（SPB）的110 kDa组分是一种必需蛋白，对酿酒酵母中功能性有丝分裂纺锤体的形成很重要。Spc110p以多种形式存在，通过SDS-聚丙烯酰胺凝胶电泳分离时迁移率不同。我们发现这种异质性是由于丝氨酸或苏氨酸残基上的差异磷酸化所致，并且Spc110p磷酸化在整个细胞周期中有所变化。具体而言，磷酸化形式的Spc110p在细胞从S期进展时出现，并且与前后期有丝分裂纺锤体的存在一致。因此，Spc110p的磷酸化发生在细胞周期中SPB获得组织有丝分裂纺锤体能力的阶段，因此可能代表一个重要的调节事件。
