GTSE1 tunes microtubule stability for chromosome alignment and segregation by inhibiting the microtubule depolymerase MCAK.

The dynamic regulation of microtubules (MTs) during mitosis is critical for accurate chromosome segregation and genome stability. Cancer cell lines with hyperstabilized kinetochore MTs have increased segregation errors and elevated chromosomal instability (CIN), but the genetic defects responsible remain largely unknown. The MT depolymerase MCAK (mitotic centromere-associated kinesin) can influence CIN through its impact on MT stability, but how its potent activity is controlled in cells remains unclear.

Combining the Optimized Yeast Cytosine Deaminase Protein Fragment Complementation Assay and an In Vitro Cdk1 Targeting Assay to Study the Regulation of the γ-Tubulin Complex.

Cdk1 is the essential cyclin-dependent kinase in the budding yeast Saccharomyces cerevisiae. Cdk1 orchestrates cell cycle control by phosphorylating target proteins with extraordinary temporal and spatial specificity by complexing with one of the nine cyclin regulatory subunits. The identification of the cyclin required for targeting Cdk1 to a substrate can help to place the regulation of that protein at a specific time point during the cell cycle and reveal information needed to elucidate the biological significance of the regulation.

Dissection of Cdk1-cyclin complexes in vivo.

Cyclin-dependent kinases (Cdks) are regulatory enzymes with temporal and spatial selectivity for their protein substrates that are governed by cell cycle-regulated cyclin subunits. Specific cyclin-Cdk complexes bind to and phosphorylate target proteins, coupling their activity to cell cycle states. The identification of specific cyclin-Cdk substrates is challenging and so far, has largely been achieved through indirect correlation or use of in vitro techniques.