Figure 4.

Model depicting role of activated Cdc28 (Cdk1) in SPB separation in budding yeast. Tyrosine dephosphorylation of Cdc28 by Mih1 leads to inactivation of Cdh1 resulting in stabilization of microtubule-associated proteins Cin8, Kip1 and Ase1 whose bundling activity catalyzes SPB separation and formation of the bipolar mitotic spindle.