High impact information on GLC8

• Mutations in the yeast Aurora, Ipl1, are suppressed by overexpression of Glc8, the yeast homolog of phosphatase inhibitor-2 (I-2) [1].
• Interestingly, overexpression as well as deletion of the GLC8 gene results in a partial suppression of the temperature-sensitive growth phenotype of ipl1ts mutants and also moderately reduces the amount of protein phosphatase 1 activity which is assayable in crude yeast lysates [2].
• In addition, the chromosome missegregation phenotype caused by an increase in the dosage of GLC7 is totally suppressed by the glc8-delta 101::LEU2 deletion mutation [2].
• Furthermore, site-directed mutagenesis studies of GLC8 suggest that Thr-118 of the Glc8 protein, which is equivalent to Thr-72 of inhibitor 2, may play a central role in the ability of this protein to activate and/or inhibit PP1C in vivo [2].
• Regulation of chromosome segregation by Glc8p, a structural homolog of mammalian inhibitor 2 that functions as both an activator and an inhibitor of yeast protein phosphatase 1 [2].

Biological context of GLC8

• In this work, we demonstrated that similarly to inhibitor-2, Glc8 function is regulated by phosphorylation [3].

Anatomical context of GLC8

• Like inhibitor 2, the Glc8 protein is heat stable, exhibits anomalous electrophoretic mobility, and functions in vitro as an inhibitor of yeast as well as rabbit skeletal muscle PP1C [2].

Associations of GLC8 with chemical compounds

• GLC8 encodes a homologue of type 1 protein phosphatase inhibitor-2 [4].
• These results are consistent with glucose repression of Glc8 expression and favor the role of Glc8 as a major Glc7 activator [5].

Other interactions of GLC8

• Deletion of the aforementioned regulatory subunits revealed that only Glc8 deletion had a significant effect in reducing Glc7 activity [5].
• In vitro kinase assays and genetic results indicate that Pho85 cyclins Pcl6 and Pcl7 comprise the predominant Glc8 kinase [3].
• Furthermore, glc7-R121K is also lethal when combined with deletions of pcl6, plc7, pcl8, and pcl10, indicating that these related cyclins redundantly activate Pho85 for Glc8 phosphorylation in vivo [3].

References