title: Glucose Starvation Alters Heat Shock Response, Leading to Death of Wild Type Cells and Survival of MAP Kinase Signaling Mutant.
abstract: A moderate heat shock induces Neurospora crassa to synthesize large quantities of heat shock proteins that are protective against higher, otherwise lethal temperatures. However, wild type cells do not survive when carbohydrate deprivation is added to heat shock. In contrast, a mutant strain defective in a stress-activated protein kinase does survive the combined stresses. In order to understand the basis for this difference in survival, we have determined the relative levels of detected proteins in the mutant and wild type strain during dual stress, and we have identified gene transcripts in both strains whose quantities change in response to heat shock or dual stress. These data and supportive experimental evidence point to reasons for survival of the mutant strain. By using alternative respiratory mechanisms, these cells experience less of the oxidative stress that proves damaging to wild type cells. Of central importance, mutant cells recycle limited resources during dual stress by undergoing autophagy, a process that we find utilized by both wild type and mutant cells during heat shock. Evidence points to inappropriate activation of TORC1, the central metabolic regulator, in wild type cells during dual stress, based upon behavior of an additional signaling mutant and inhibitor studies.
authors.affiliation: Department of Plant Biology, University of Minnesota, Saint Paul, Minnesota, United States of America.
authors.forename: Nora
authors.identifier: http://orcid.org/0000-0002-6213-0930
authors.initials: N
authors.lastname: Plesofsky
authors.affiliation: Department of Biochemistry, University of Minnesota, Saint Paul, Minnesota, United States of America.
authors.forename: LeeAnn
authors.initials: L
authors.lastname: Higgins
authors.affiliation: Department of Biochemistry, University of Minnesota, Saint Paul, Minnesota, United States of America.
authors.forename: Todd
authors.initials: T
authors.lastname: Markowski
authors.affiliation: Department of Plant Biology, University of Minnesota, Saint Paul, Minnesota, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Brambl
mesh_terms: D001343:Autophagy; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism*; D018869:Heat-Shock Response; D006358:Hot Temperature; D020935:MAP Kinase Signaling System; D050296:Microbial Viability; D009154:Mutation; D009492:Neurospora crassa / Q000235:genetics / Q000254:growth & development*; D018384:Oxidative Stress
chemical_list: D005656:Fungal Proteins; D005947:Glucose