tailieunhanh - Báo cáo Y học: Cold induces stress-activated protein kinase-mediated response in the fission yeast Schizosaccharomyces pombe

In the fission yeastSchizosaccharomyces pombethe Wak1p/ Win1p-Wis1p-Sty1p stress-activated protein kinase (SAPK) pathway relays environmental signals to the transcriptional machinery and modulates gene expression via a cascade of proteinphosphorylation. Cells ofS. pombesubjected tocold shock (transfer from 28 Cto15 C) transiently activated the Sty1p mitogen-activated protein kinase (MAPK) by phosphorylation. | Eur. J. Biochem. 269 5056-5065 2002 FEBS 2002 doi Cold induces stress-activated protein kinase-mediated response in the fission yeast Schizosaccharomyces pombe Teresa Soto1 Francisco F. Beltran1 Vanessa Paredes1 Marisa Madrid1 Jonathan B. A. Millar2 . . B. Jero Vicente-Soler1 Jose Cansado1 and Mariano Gacto1 1Departamento de Genetica y Microbiologia Facultad de Biologia Universidad de Murcia Spain 2Division of Yeast Genetics National Institute for Medical Research London UK In the fission yeast Schizosaccharomycespombe the Wak1p Win1p-Wis1p-Sty1p stress-activated protein kinase SAPK pathway relays environmental signals to the transcriptional machinery and modulates gene expression via a cascade of protein phosphorylation. Cells of S. pombe subjected to cold shock transfer from 28 C to 15 C transiently activated the Sty1p mitogen-activated protein kinase MAPK by phosphorylation. Induction of this response was completely abolished in cells disrupted in the upstream response regulator Mcs4p. The cold-triggered Sty1p activation was partially dependent on Wak1p MAPKKK and fully dependent on Wis1p MAPKK suggesting that the signal transmission follows a branched pathway with the redundant MAPKKK Win1p as alternative transducer to Wis1p which subsequently activates the effector Sty1p MAPK. Also the bZIP transcription factor Atf1p became phosphorylated in a Sty1p-dependent way duringthe cold shock and this phosphorylation was found responsible for the increased expression of gpd1 ctt1 tps1 and ntp1 genes. Strains deleted in transcription factors Atf1p or Pcr1p were unable to grow upon incubation at low temperature whereas those disrupted in any member of the SAPK pathway were able to do so. These data reveal that S. pombe responds to cold by inducingthe SAPK pathway. However such activation is dispensable for yeast growth in cold conditions supporting that the presence of Atf1 Pcr1 heterodimers rather than an operative SAPK pathway is .