ABSTRACT
RSC is a 15-protein ATP-dependent chromatin-remodeling complex related to Snf-Swi, the prototypical ATP-dependent nucleosome remodeler in budding yeast. Despite insight into the mechanism by which purified RSC remodels nucleosomes, little is known about the chromosomal targets or cellular pathways in which RSC acts. To better understand the cellular function of RSC, a screen was undertaken for gene dosage suppressors of sth1-3ts, a temperature-sensitive mutation in STH1, which encodes the essential ATPase subunit. Slg1p and Mid2p, two type I transmembrane stress sensors of cell wall integrity that function upstream of protein kinase C (Pkc1p), were identified as multicopy suppressors of sth1-3ts cells. Although the sth1-3ts mutant exhibits defects characteristic of PKC1 pathway mutants (caffeine and staurosporine sensitivities and an osmoremedial phenotype), only upstream components and not downstream effectors of the PKC1-MAP kinase pathway can suppress defects conferred by sth1-3ts, suggesting that RSC functions in an alternative PKC1-dependent pathway. Moreover, sth1-3ts cells display defects in actin cytoskeletal rearrangements and are hypersensitive to the microtubule depolymerizing drug, TBZ; both of these defects can be corrected by the high-copy suppressors. Together, these data reveal an important functional connection between the RSC remodeler and PKC1-dependent signaling in regulating the cellular architecture.
Subject(s)
Cell Cycle Proteins , Cytoskeleton/metabolism , DNA-Binding Proteins/physiology , MAP Kinase Signaling System/physiology , Nuclear Proteins , Protein Kinase C/metabolism , Saccharomyces cerevisiae/physiology , Transcription Factors/physiology , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Enzyme Activators/metabolism , Hot Temperature , Intracellular Signaling Peptides and Proteins , Membrane Glycoproteins , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mutation , Protein Kinase C/genetics , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Thiabendazole/antagonists & inhibitors , Thiabendazole/metabolism , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
In ICR mice depleted of glutathione (GSH) by treatment with DL-buthionine sulphoximine (BSO), males were much more susceptible to thiabendazole (TBZ) nephrotoxicity than females. The nephrotoxicity was indicated by increases in relative kidney weight and serum urea nitrogen (SUN) concentration and by a decrease in renal GSH concentration at 24 hr after TBZ administration. The susceptibility of males to TBZ-induced nephrotoxicity was completely eliminated by pretreatment with oestradiol (OD). Castration of male mice also reduced, though not completely, their susceptibility to TBZ nephrotoxicity. In females pretreated with testosterone (TS), the nephrotoxic effect of TBZ was increased to an extent comparable with that in males.
