FIGURE 6:

Sid2 kinase activity correlates with Cdc7 asymmetry. (A) Cells were synchronized by centrifugal elutriation and samples were collected at the indicated intervals. Cell cycle progression was monitored by determining the septation index and the appearance of Cdc7-GFP at one or two SPBs. Sid2-Myc was also immunoprecipitated from samples collected at each time point and assayed for activity toward MBP-Cdc11-(1-660) and MBP. The amount of Sid2 in each kinase assay was determined by immunoblotting, and the amount of protein in each lysate was controlled by the amount of Cdc2 determined by immunoblotting with anti-PSTAIRE. (B) Sid2-Myc was immunoprecipitated from the indicated strains and assayed for activity toward MBP. The amount of Sid2 immunoprecipitated and the amount of protein in each lysate prior to immunoprecipitation was determined by immunoblotting. (C) Speculative model of Cdc11 phosphoregulation. The dotted arrow indicates the activation of Sid2 by Cdc7 through Sid1, which is not shown. Asterisks indicate more active forms of Cdc7 and Sid2 kinases.