Mitosis inducer protein kinase cdr2

[1] Cdr2 regulates mitotic entry through direct inhibition of Wee1, which is then unable to continue to Cdk1 and subsequently start mitosis.

The C-terminus is required for correct localization; cleavage of any number of residues close to the carboxy terminus results in abnormal distribution.

[2] When the cell enters mitosis, Cdr2 is distributed diffusely through the cytoplasm; there is no detectable cortical band in metaphase in anaphase.

Once phosphorylated, Cdr2 is unable to inhibit the kinase Wee1, which is then able to maintain CDK1 in a hyper-phosphorylated state incapable of progression into mitosis.

In larger cells, there is much lower degree of overlap between Pom1 and Cdr2, allowing Cdr2 to inhibit Wee1; CDK1 is then able to promote mitotic entry.

Figure 1: Accepted Model for Cdr2's indirect promotion of mitotic entry. Cdr2 is suppressed by Pom1, and is unable to phosphorylate Wee1 to activate CDK1.
Figure 2: Difference in Pom1 and Cdr2 overlap in small cells and big cells.