KNR4 is a member of the PKC1 signalling pathway and genetically interacts with BCK2, a gene involved in cell cycle progression in Saccharomyces cerevisiae.
In budding yeast, PKC1 plays an essential role in cell wall integrity and cell proliferation through a bifurcated PKC1/mitogen-activated protein (MAP) kinase pathway. The evidence that KNR4 is a member of the PKC1 pathway and genetically interacts with BCK2, a gene involved together with Cln3-Cdc28 in the G1 to S transition phase of the cell cycle, was as follows. Both KNR4 and BCK2 were isolated as a dosage suppressor of a calcofluor white hypersensitive ( cwh43) mutant. Overexpression of either of the two genes in a wild-type strain led to increased resistance to wall-affecting drugs, while this effect was not obtained in a bck2 Delta mutant that overexpressed KNR4. Deletion of KNR4 or BCK2 was synthetically lethal with components of the linear PKC1/MAP kinase pathway. Loss of Knr4 was lethal in combination with loss of Cln3, as was shown for Bck2. A protein interaction between Knr4 and Bck2 was measured using the two-hybrid system, although a direct physical interaction could not be detected by co-immunuprecipation methods. Finally, a genome-wide analysis of cells that overexpress BCK2 or KNR4 indicated that both genes also have effects independent of each other. In particular, the microarray data showed up-regulation of SWI4, which may account for the suppression of the cell lysis of a pkc1 null mutant, due to overexpression of BCK2.
Centre de Bioingenierie Gilbert Durand, UMR-CNRS 5504, UR-INRA 792, 31077 Toulouse, France.
Helene
H
Martin-Yken
Adilia
A
Dagkessamanskaia
Driss
D
Talibi
Jean
J
Francois
D056746:Cyclin G; D016213:Cyclins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000235:genetics* / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors
C082733:BCK2 protein, S cerevisiae; D056746:Cyclin G; D016213:Cyclins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; C085451:SMI1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C097993:Pkc1 protein, Trichoderma reesei; D011493:Protein Kinase C