title: Hsp70-Hsp40 chaperone complex functions in controlling polarized growth by repressing Hsf1-driven heat stress-associated transcription.
abstract: How the molecular mechanisms of stress response are integrated at the cellular level remains obscure. Here we show that the cellular polarity machinery in the fission yeast Schizosaccharomyces pombe undergoes dynamic adaptation to thermal stress resulting in a period of decreased Cdc42 activity and altered, monopolar growth. Cells where the heat stress-associated transcription was genetically upregulated exhibit similar growth patterning in the absence of temperature insults. We identify the Ssa2-Mas5/Hsp70-Hsp40 chaperone complex as repressor of the heat shock transcription factor Hsf1. Cells lacking this chaperone activity constitutively activate the heat-stress-associated transcriptional program. Interestingly, they also exhibit intermittent monopolar growth within a physiological temperature range and are unable to adapt to heat stress. We propose that by negatively regulating the heat stress-associated transcription, the Ssa2-Mas5 chaperone system could optimize cellular growth under different temperature regiments.
authors.affiliation: Temasek Life Sciences Laboratory, Singapore ; Department of Biological Sciences, National University of Singapore, Singapore.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Vjestica
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Liu
authors.forename: Snezhana
authors.initials: S
authors.lastname: Oliferenko
mesh_terms: D016764:Cell Polarity / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006358:Hot Temperature; D018832:Molecular Chaperones / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development; D013312:Stress, Physiological / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: D004268:DNA-Binding Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D018832:Molecular Chaperones; D014157:Transcription Factors