Selective Inhibitors of the Proteasome-dependent and Vacuolar Pathways of Protein Degradation in Saccharomyces cerevisiae

Lee, Do Hee; Goldberg, Alfred L.

doi:10.1074/jbc.271.44.27280

Cited by 376 publications

(329 citation statements)

References 33 publications

(35 reference statements)

Supporting

Mentioning

313

Contrasting

Order By: Relevance

“…To investigate specific proteolytic pathways that may be involved in the destruction of BRCA1 protein during heating, we tested several protease inhibitors for their ability to block the loss of BRCA1 during heat shock. MG132 is a potent inhibitor of the 26S proteasome, which strongly inhibits the classic ubiquitin/proteasomal degradation pathway (Lee and Goldberg, 1996). Whether MG132 (10 mM) was present during heat shock (421C Â 2 h) or for 6 h prior to as well as during heat shock, there was no recovery of the BRCA1 protein levels in either DU-145 cells (Figure 11a) or MCF-7 cells (data not shown).…”

Section: Structural Requirements For the Heat-induced Degradation Of mentioning

confidence: 83%

Role of BRCA1 in heat shock response

et al. 2003

View full text Add to dashboard Cite

The heat shock response is an evolutionarily conserved response to heat and other stresses that promotes the maintenance of key metabolic functions and cell survival. We report that exposure of human prostate (DU-145) and breast (MCF-7) cancer cells to heat (421C) caused a rapid disappearance of the breast cancer susceptibility gene-1 (BRCA1) protein, starting at E1 h after the onset of heating and slightly lagging behind the increase in heat shock protein 70 (HSP70) levels. The heat-induced loss of BRCA1 occurred at the protein level, since: (1) BRCA1 mRNA expression was unaffected; and (2) the BRCA1 protein loss was also observed in DU-145 cells that expressed exogenous wild-type BRCA1 (wtBRCA1). In addition to heat regulation of BRCA1 protein levels, we also found that BRCA1 could modulate the heat shock response. Thus, wtBRCA1 overexpressing DU-145 cell clones showed significantly decreased sensitivity to heatinduced cytotoxicity; and Brca1 mutant mouse embryo fibroblasts showed increased sensitivity to heat. The DU-145 wtBRCA1 clones also showed increased expression of the small heat shock protein HSP27; and reporter assays revealed that wtBRCA1 stimulated a two to four-fold increase in HSP27 promoter activity, consistent with its ability to upregulate HSP27 mRNA and protein levels. In studies using epitope-tagged truncated BRCA1 proteins, the ability to stimulate the HSP27 promoter and to mediate heat-induced degradation required the aminoterminus but not the carboxyl-terminus of BRCA1. Although the heat-induced loss of BRCA1 appeared to be due to protein degradation, various protein metabolic agents (or combinations) failed to block this event, including: MG132 (a 26S proteasomal inhibitor), Nacetyl-leucyl-leucyl-norleucinal (a calpain inhibitor), z-VAD-fmk (a pan-caspase inhibitor), and ammonium chloride and chloroquine (which stabilize lysosomes). These findings suggest that in addition to its other functions, BRCA1 may participate in mammalian heat shock response pathways.

show abstract

Section: Structural Requirements For the Heat-induced Degradation Of mentioning

confidence: 83%

Role of BRCA1 in heat shock response

et al. 2003

View full text Add to dashboard Cite

show abstract

“…Studies using catalytic site-specific mutants of yeast proteasome and site-specific inhibitors have demonstrated that the chymotrypsin-like activity primarily determines the rate of protein degradation (Craiu et al, 1997;Lee and Goldberg, 1996). Therefore, the inhibition of this activity probably has the most significant consequences for key processes involved in cell survival.…”

Section: Consequences Of Proteasome Inhibitionmentioning

confidence: 99%

“…The inner two rings contain the β subunits. Three of the β subunits (β1, β2, β5) contain the catalytic sites that perform distinct proteolytic activities (Craiu et al, 1997;Lee and Goldberg, 1996;Rock et al, 1994). These activities are classified as caspase-like (β1), trypsin-like (β2), and chymotrypsin-like (β5) as defined by cleavage after acidic, basic, or hydrophobic amino acids, respectively.…”

Section: Introductionmentioning

confidence: 99%

Age-dependent inhibition of proteasome chymotrypsin-like activity in the retina

Kapphahn

Bigelow

Ferrington

2007

Experimental Eye Research

View full text Add to dashboard Cite

The proteasome plays a fundamental role in processes essential for cell viability. A loss in proteasome function has been associated with aging, as well as a number of age-related diseases. Defining the mechanism(s) behind this loss in function will add important information regarding the molecular basis for aging. In the current study, we performed an age-based comparison of proteasome function and composition of subunits and regulatory proteins in the neural retina and retinal pigment epithelium (RPE) in Fischer 344 rats. In the RPE, there was no age-dependent difference in activity, subunit composition, or content of proteasome regulators, PA28 and PA700. In contrast, the aged neural retina demonstrated a significant reduction in the chymotrypsin-like activity and decreased degradation of both casein and casein modified by 4-hydroxynonenal. This loss in function could not be explained by differences in subunit composition, content of PA28 and PA700, or reversible modification of cysteine residues. To begin investigating the molecular basis for the age-associated decrement in proteasome function, we modified the cysteine residues in proteasome from young rats with the sulfhydryl reactive chemical N-ethylmaleimide. We observed inhibition of the chymotrypsin-like activity and decreased degradation of casein that was comparable to that seen in aged retinas. Thus, chemical modification of cysteine provides an in vitro method that partially recapitulates aging proteasome. Further studies are required to confirm irreversible modification of functionally significant cysteine as a potential mechanism behind the age-related loss in proteasome function.

show abstract

“…To test the possibility that YkB is a general proteasome inhibitor, we examined the effects of YkB on ATP-dependent proteasome activity using Arabidopsis T-87 cells and an S. cerevisiae ise1 (erg6) strain expressing ubiquitin-␤-galactosidase fusion protein as proteasome substrate under the control of the GAL4 promoter (39,40). The ise1 yeast strain was chosen to preclude detoxification of the drug by pumping via multidrug resistance channels (41).…”

Section: Ykb Blocks Primary Auxin-responsive Gene Expressionmentioning

confidence: 99%

Yokonolide B, a Novel Inhibitor of Auxin Action, Blocks Degradation of AUX/IAA Factors

Hayashi

Jones

Ogino

et al. 2003

Journal of Biological Chemistry

View full text Add to dashboard Cite

Yokonolide B (YkB; also known as A82548A), a spiroketal-macrolide, was isolated from Streptomyces diastatochromogenes B59 in a screen for inhibitors of ␤-glucoronidase expression under the control of an auxin-responsive promoter in Arabidopsis. YkB inhibits the expression of auxin-inducible genes as shown using native and synthetic auxin promoters as well as using expression profiling of 8,300 Arabidopsis gene probes but does not affect expression of an abscisic acid-and a gibberellin A 3 -inducible gene. The mechanism of action of YkB is to block AUX/IAA protein degradation; however, YkB is not a general proteasome inhibitor. YkB blocks auxin-dependent cell division and auxin-regulated epinastic growth mediated by auxin-binding protein 1. Gain of function mutants such as shy2-2, slr1, and axr2-1 encoding AUX/IAA transcriptional repressors and loss of function mutants encoding components of the ubiquitin-proteolytic pathway such as axr1-3 and tir1-1, which display increased AUX/IAAs protein stability, are less sensitive to YkB, although axr1 and tir1 mutants were sensitive to MG132, a general proteasome inhibitor, consistent with a site of action downstream of AXR1 and TIR. YkB-treated seedlings displayed similar phenotypes as dominant AUX/IAA mutants. Taken together, these results indicate that YkB acts to block AUX/IAA protein degradation upstream of AXR and TIR, links a shared element upstream of AUX/IAA protein stability to auxin-induced cell division/elongation and to auxin-binding protein 1, and provides a new tool to dissect auxin signal transduction.Auxin controls cell division, elongation, and differentiation and therefore, through its action at the level of the cell, exerts profound effects on growth and development throughout the life of the plant (1). Consistent with the diverse effects of auxin on growth and development is that the expression patterns of a number of genes are dramatically and rapidly altered by auxin application (2), suggesting that auxin ultimately regulates cell growth by controlling the profile of expressed genes. AUX/IAA genes comprise a 34-member gene family in Arabidopsis that is one of three known gene families that are regulated by auxin and implicated to play essential roles in auxin signaling (3, 4).The molecular and genetic studies on auxin signaling have revealed that auxin specifically enhances the transcription of many AUX/IAA genes within minutes without requiring de novo protein synthesis, suggesting that AUX/IAA genes are primary auxin-response genes (5, 6). AUX/IAA genes encode short lived nuclear proteins capable of heterodimerization with auxin-responsive factors (7) and are thought to act by negatively regulating the expression of early auxin-responsive genes including other members of the AUX/IAA family (3).Studies on Arabidopsis mutants with altered responses to auxin such as iaa3/shy2-2, iaa7/axr2-1, iaa17/axr3, iaa14/slr1, tir1, and axr1 revealed that the turnover rate of AUX/IAA proteins is in some way important in various developmental processes including ...

show abstract

Selective Inhibitors of the Proteasome-dependent and Vacuolar Pathways of Protein Degradation in Saccharomyces cerevisiae

Cited by 376 publications

References 33 publications

Role of BRCA1 in heat shock response

Role of BRCA1 in heat shock response

Age-dependent inhibition of proteasome chymotrypsin-like activity in the retina

Yokonolide B, a Novel Inhibitor of Auxin Action, Blocks Degradation of AUX/IAA Factors

Contact Info

Product

Resources

About