Rc. Santos et al., STRUCTURE-FUNCTION-RELATIONSHIPS OF THE YEAST CYCLIN-DEPENDENT KINASEPHO85, Molecular and cellular biology, 15(10), 1995, pp. 5482-5491
The PHO85 gene of Saccharomyces cerevisiae encodes a cyclin-dependent
kinase involved in both transcriptional regulation and cell cycle prog
ression. Although a great deal is known concerning the structure, func
tion, and regulation of the highly homologous Cdc28 protein kinase, li
ttle is known concerning these relationships in regard to Pho85. In th
is study, we constructed a series of Pho85-Cdc28 chimeras to map the r
egion(s) of the Pho85 molecule that is critical for function of Pho85
in repression of acid phosphatase (PHO5) expression. Using a combinati
on of site-directed and ethyl methanesulfonate-induced mutagenesis, we
have identified numerous residues critical for either activation of t
he Pho85 kinase, interaction of Pho85 with the cyclin-like molecule Ph
o80, or substrate recognition. Finally, analysis of mutations analogou
s to those previously identified in either Cdc28 or cdc2 of Schizosacc
haromyces pombe suggested that the inhibition of Pho85-Pho80 activity
is mechanistically different from that seen in the other cyclin-depend
ent kinases.