FIGURE 2:

Cytokinesis-specific association of Hof1 and Cyk3 and its apparent independence from the concomitant (hyper)phosphorylation. (A) Cytokinesis-specific association of Hof1 and Cyk3. Strain MWY1025 (CYK3-GFP HOF1-TAP cdc15-2) was grown to exponential phase in YM-P medium at 24°C, shifted to 37°C for 3 h to arrest the cell cycle at mitotic exit, and then released from arrest by shifting to 24°C. See Figure 3A for images of the cells from each time point. Cells were collected at the indicated times after release, and coprecipitation assays were performed as in Figure 1C. Protein extracts loaded in the input lanes were 1/40 of the amounts used for the IP lanes. (B) Phosphorylation of Cyk3 and apparent independence of Hof1–Cyk3 association from the cell-cycle–regulated (hyper)phosphorylation of both proteins. Strains MWY1025 (lanes 1–4) and MWY2117 (CYK3-TAP HOF1-3HA cdc15-2; lanes 5–8) were synchronized as in A, and cells were collected 45 min after release. Hof1-TAP or Cyk3-TAP was precipitated, and precipitates were subjected to phosphatase (PPase) treatments as indicated.