title: Latrunculin A-Induced Perturbation of the Actin Cytoskeleton Mediates Pap1p-Dependent Induction of the Caf5p Efflux Pump inSchizosaccharomyces pombe.
abstract: As part of an earlier study aimed at uncovering gene products with roles in defending against latrunculin A (LatA)-induced cytoskeletal perturbations, we identified three members of the oxidative stress response pathway: the Pap1p AP-1-like transcription factor, the Imp1p α-importin, and the Caf5p efflux pump. In this report, we characterize the pathway further and show that Pap1p translocates from the cytoplasm to the nucleus in an Imp1p-dependent manner upon LatA treatment. Moreover, preventing this translocation, through the addition of a nuclear export signal (NES), confers the same characteristic LatA-sensitive phenotype exhibited bypap1Δ cells. Lastly, we show that thecaf5gene is induced upon exposure to LatA and that Pap1p is required for this transcriptional upregulation. Importantly, the expression oftrr1, a Pap1p target specifically induced in response to oxidative stress, is not significantly altered by LatA treatment. Taken together, these results suggest a model in which LatA-mediated cytoskeletal perturbations are sensed, triggering the Imp1p-dependent translocation of Pap1p to the nucleus and the induction of thecaf5gene (independently of oxidative stress).
authors.affiliation: Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
authors.forename: Farzad
authors.initials: F
authors.lastname: Asadi
authors.affiliation: Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
authors.forename: Bidhan
authors.initials: B
authors.lastname: Chakraborty
authors.affiliation: Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7, Canada jkaragia@uwo.ca.
authors.forename: Jim
authors.initials: J
authors.lastname: Karagiannis
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics* / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics; D003593:Cytoplasm / Q000187:drug effects / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics*; D049790:Nuclear Export Signals / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics*; D015398:Signal Transduction / Q000187:drug effects; D053778:Thiazolidines / Q000494:pharmacology; D028901:alpha Karyopherins / Q000235:genetics*
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D019086:Bridged Bicyclo Compounds, Heterocyclic; C484808:Caf5 protein, S pombe; D008565:Membrane Proteins; D049790:Nuclear Export Signals; C105096:Pap1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D053778:Thiazolidines; D028901:alpha Karyopherins; C087978:karyopherin alpha 2; C037067:latrunculin A
keywords: actin cytoskeleton; cell division; fission yeast; latrunculin A; stress response