G1 cyclin turnover and nutrient uptake are controlled by a common pathway in yeast.
Entry into a new cell cycle is triggered by environmental signals at a point called Start in G1 phase. A key regulator of this transition step in yeast is the CDC28 kinase together with its short-lived regulatory subunits called G1-cyclins or CLN proteins. To identify genes involved in G1-cyclin degradation, we employed a genetic screen by selecting for stable CLN1-beta-galactosidase fusion proteins. Surprisingly, one group of mutants was found to be allelic to GRR1, a gene previously described to be involved in glucose uptake, glucose repression, and divalent cation transport. In grr1 mutants, both CLN1 and CLN2 cyclins are significantly stabilized. A suppressor analysis indicated that G1-cyclin stabilization in grr1 was not a consequence of the nutrient uptake defect. This suggests that the GRR1 gene product is part of a common regulatory pathway linking two functions important for cell growth, nutrient uptake, and G1 cyclin-controlled cell division.
Barral
Y
Y
Départment de Biologie Cellulaire et Moléculaire, Centre d'Etudes de Saclay, Gif-sur-Yvette, France.
Jentsch
S
S
Mann
C
C
D001692:Biological Transport; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics*; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D044783:F-Box Proteins; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D016193:G1 Phase / Q000235:genetics / Q000502:physiology*; D005800:Genes, Fungal / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D009024:Morphogenesis; D011233:Precipitin Tests; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D044767:Ubiquitin-Protein Ligases
C082719:CLN1 protein, S cerevisiae; C082721:CLN2 protein, S cerevisiae; C079895:CLN3 protein, S cerevisiae; D002352:Carrier Proteins; D016213:Cyclins; D044783:F-Box Proteins; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C071032:GRR1 protein, S cerevisiae; D044767:Ubiquitin-Protein Ligases; D005947:Glucose