title: Low temperature highlights the functional role of the cell wall integrity pathway in the regulation of growth in Saccharomyces cerevisiae.
abstract: Unlike other stresses, the physiological significance and molecular mechanisms involved in the yeast cold response are largely unknown. In the present study, we show that the CWI (cell wall integrity) pathway plays an important role in the growth of Saccharomyces cerevisiae at low temperatures. Cells lacking the Wsc1p (wall integrity and stress response component 1) membrane sensor or the MAPKs (mitogen-activated protein kinases) Bck1p (bypass of C kinase 1), Mkk (Mapk kinase) 1p/Mkk2p or Slt2p (suppressor of lyt2) exhibited cold sensitivity. However, there was no evidence of either a cold-provoked perturbation of the cell wall or a differential cold expression program mediated by Slt2p. The results of the present study suggest that Slt2p is activated by different inputs in response to nutrient signals and mediates growth control through TORC1 (target of rapamycin 1 complex)-Sch9p (suppressor of cdc25) and PKA (protein kinase A) at low temperatures. We found that absence of TOR1 (target of rapamycin 1) causes cold sensitivity, whereas a ras2Δ mutant shows increased cold growth. Lack of Sch9p alleviates the phenotype of slt2Δ and bck1Δ mutant cells, as well as attenuation of PKA activity by overexpression of BCY1 (bypass of cyclase mutations 1). Interestingly, swi4Δ mutant cells display cold sensitivity, but the phenotype is neither mediated by the Slt2p-regulated induction of Swi4p (switching deficient 4)-responsive promoters nor influenced by osmotic stabilization. Hence, cold signalling through the CWI pathway has distinct features and might mediate still unknown effectors and targets.
authors: Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7. 46980-Paterna, Valencia, Spain.
authors: Isaac
authors: I
authors: Córcoles-Sáez
authors: Lídia
authors: L
authors: Ballester-Tomas
authors: Maria A
authors: MA
authors: de la Torre-Ruiz
authors: Jose A
authors: JA
authors: Prieto
authors: Francisca
authors: F
authors: Randez-Gil
mesh_terms: D002473:Cell Wall / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029701:Saccharomyces cerevisiae Proteins; C561842:TORC1 protein complex, S cerevisiae; D014157:Transcription Factors; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae