The G1 @entity1364 @entity35762 negatively regulates the mating-factor pathway. In a genetic screen to identify factors required for this regulation, we identified an allele of CDC28 ( @entity9362 ) that blocked this function of @entity35762 . @entity35762 immunoprecipitated from @entity9362 cells was completely defective in histone H1 kinase activity, due to defects in Cdc28 binding and activation by @entity35762 . In contrast, Clb2-associated H1 kinase and Cdc28 binding was normal in immunoprecipitates from these cells. @entity9362 was significantly deficient in other aspects of genetic interaction with @entity35762 . The @entity9362 mutation was determined to be @entity69985 , in the T loop distal to most of the probable Cdk- @entity1364 interaction regions. We performed random mutagenesis of CDC28 to identify additional alleles incapable of causing @entity35762 -dependent mating-factor resistance but capable of complementing cdc28 temperature-sensitive and null alleles. Two such mutants had highly defective @entity35762 -associated kinase, but, surprisingly, two other mutants had levels of @entity35762 -associated kinase near to wild-type levels. We performed a complementary screen for CDC28 mutants that could cause efficient @entity35762 -dependent mating-factor resistance but not complement a cdc28 null allele. Most such mutants were found to alter residues essential for kinase activity; the proteins had little or no associated kinase activity in bulk or in association with @entity35762 . Several of these mutants also functioned in another assay for @entity35762 -dependent function not involving the mating-factor pathway, complementing the temperature sensitivity of a cln1 cln3 @entity9362 strain. These results could indicate that @entity35762 -Cdc28 kinase activity is not directly relevant to some @entity35762 -mediated functions. Mutants of this sort should be useful in differentiating the function of Cdc28 complexed with different @entity1364 regulatory subunits.

Isolation and characterization of new alleles of the XXXX -dependent kinase gene CDC28 with @entity1364 -specific functional and biochemical defects.

@entity9362 :: ('51435', 'Gene') :: ['cdc28-csr1'] @entity69985 :: ('p|SUB|Q|188|P', 'ProteinMutation') :: ['Q188P'] @entity1364 :: ('5111', 'Gene') :: ['cyclin'] @entity35762 :: ('1200', 'Gene') :: ['Cln2', 'CLN2']
@entity1364 :: (5111,Gene) :: ['cyclin']
