Distinct Machinery Is Required in Saccharomyces cerevisiae for the Endoplasmic Reticulum-associated Degradation of a Multispanning Membrane Protein and a Soluble Luminal Protein

Huyer, Gregory; Piluek, Wachirapon F.; Fansler, Zoya; Kreft, Stefan G.; Hochstrasser, Mark; Brodsky, Jeffrey L.; Michaelis, Susan

doi:10.1074/jbc.m402468200

Cited by 251 publications

(317 citation statements)

References 74 publications

(107 reference statements)

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“…Recently, it was reported that a membrane protein and a soluble luminal protein in the ER were degraded by distinct cellular mechanisms (Taxis et al, 2003;Huyer et al, 2004;Vashist and Ng, 2004). In addition, two ER surveillance mechanisms have been proposed: ERAD-L, which monitors the folded state of luminal domains; and ERAD-C, which monitors that of cytosolic domains (Ahner and Brodsky, 2004;Vashist and Ng, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…We further examined the role of ubiquitin ligases (E3) in the degradation of Gas1*p. We selected three kinds of E3 that are thought to be involved in ERAD pathway, including the gene products of HRD1, which is involved in ERADlumenal (ERAD-L) pathway (Ahner and Brodsky, 2004;Huyer et al, 2004;Vashist and Ng, 2004); DOA10, which is involved in ERAD-cytosolic (ERAD-C) pathway; and RSP5, which is assumed to be involved in ERAD of misfolded protein when overproduced (Haynes et al, 2002). Unexpectedly, the degradation of HA-Gas1*p was not stabilized in hrd1⌬ and doa10⌬ cells ( Figure 5A).…”

Section: Construction and Characterization Of Misfolded Gas1mentioning

confidence: 99%

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Inositol Deacylation by Bst1p Is Required for the Quality Control of Glycosylphosphatidylinositol-anchored Proteins

Fujita

Yoko-o

Jigami

2006

MBoC

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Misfolded proteins are recognized in the endoplasmic reticulum (ER), transported back to the cytosol, and degraded by the proteasome. A number of proteins are processed and modified by a glycosylphosphatidylinositol (GPI) anchor in the ER, but the quality control mechanisms of GPI-anchored proteins remain unclear. Here, we report on the quality control mechanism of misfolded GPI-anchored proteins. We have constructed a mutant form of the ␤-1,3-glucanosyltransferase Gas1p (Gas1*p) as a model misfolded GPI-anchored protein. Gas1*p was modified with a GPI anchor but retained in the ER and was degraded rapidly via the proteasome. Disruption of BST1, which encodes GPI inositol deacylase, caused a delay in the degradation of Gas1*p. This delay was because of an effect on the deacylation activity of Bst1p. Disruption of genes involved in GPI-anchored protein concentration and N-glycan processing caused different effects on the degradation of Gas1*p and a soluble misfolded version of carboxypeptidase Y. Furthermore, Gas1*p associated with both Bst1p and BiP/Kar2p, a molecular chaperone, in vivo. Our data suggest that GPI inositol deacylation plays important roles in the quality control and ER-associated degradation of GPI-anchored proteins. INTRODUCTIONCells possess several quality control mechanisms for the maintenance of proper protein folding and function. On synthesis, membrane and secretory proteins are inserted into the lumen of the endoplasmic reticulum (ER), where they are folded and undergo oligomerization. There are a number of chaperones and enzymes in the ER required for proper protein folding (Ellgaard et al., 1999). Before exiting from the ER, proteins are monitored by a quality control system that ensures correct folding. Misfolded proteins that fail to pass the quality control checkpoint are transported back to the cytosol and degraded by an ER-associated degradation (ERAD) mechanism that involves the ubiquitinproteasome pathway (Kopito, 1997;Kostova and Wolf, 2003). N-linked oligosaccharide, one of the major posttranslational modifications in the ER, is trimmed and processed by glucosidase I, glucosidase II, and mannosidase I (Jakob et al., 1998;Helenius and Aebi, 2001). The processing of Nlinked oligosaccharides plays important roles in the quality control of glycoprotein folding in the ER Aebi, 2001, 2004).A number of cell surface proteins are posttranslationally modified in the ER with glycosylphosphatidylinositol (GPI). Mechanisms for quality control and degradation of GPIanchored proteins are important in folding diseases, including prion diseases and transmissible spongiform encephalopathies, which are caused by a conformational modification of prion, a GPI-anchored protein (Prusiner, 1998). There have been several biochemical studies on both the degradation of mutated prions and the quality control of proteins with mutated GPI attachment signals (Field et al., 1994;Oda et al., 1996;Wainwright and Field, 1997;Jin et al., 2000;Ito et al., 2002;Ishida et al., 2003). In contrast, the molecular mech...

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Section: Discussionmentioning

confidence: 99%

Section: Construction and Characterization Of Misfolded Gas1mentioning

confidence: 99%

Inositol Deacylation by Bst1p Is Required for the Quality Control of Glycosylphosphatidylinositol-anchored Proteins

Fujita

Yoko-o

Jigami

2006

MBoC

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“…Not only is this process energetically expensive but also it challenges the cell to prevent these proteins from forming insoluble aggregates when the hydrophobic TMs are exposed to the hydrophilic environment of the cytosol. Indeed, specific AAA-ATPases, such as p97, and other molecular chaperones provide the driving force for dislocation and prevention of protein aggregation (Nishikawa et al, 2001;Ye et al, 2001;Elkabetz et al, 2004;Huyer et al, 2004;Bar-Nun, 2005;Buck et al, 2007;Lipson et al, 2008). The current study describes a system that should allow dissecting the steps in dislocation of polytopic ERAD substrates en route to proteasomal degradation and identification of cellular components that take part in this process.…”

Section: Discussionmentioning

confidence: 99%

Dislocation of HMG-CoA Reductase and Insig-1, Two Polytopic Endoplasmic Reticulum Proteins, En Route to Proteasomal Degradation

Leichner

Avner

Harats

et al. 2009

MBoC

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The endoplasmic reticulum (ER) glycoprotein HMG-CoA reductase (HMGR) catalyzes the rate-limiting step in sterols biosynthesis. Mammalian HMGR is ubiquitinated and degraded by the proteasome when sterols accumulate in cells, representing the best example for metabolically controlled ER-associated degradation (ERAD). This regulated degradation involves the short-lived ER protein Insig-1. Here, we investigated the dislocation of these ERAD substrates to the cytosol en route to proteasomal degradation. We show that the tagged HMGR membrane region, HMG 350 INTRODUCTIONA key mechanism for maintaining cholesterol homeostasis in mammalian cells involves modulating the stability of 3-hydroxy-3-methylglutaryl CoA reductase (HMGR). This enzyme catalyzes the rate-limiting step in the mevalonate (MVA) pathway in which essential sterols and nonsterol isoprenoids are synthesized (Goldstein and Brown, 1990). In cells deprived of sterols and/or MVA-derived isoprenoids, HMGR is a fairly stable protein that turns over with a half-life of 10 -14 h. Conversely, in cells replenished with MVA pathway products, HMGR degradation is accelerated severalfold and its half-life drops to 1-4 h (Faust et al., 1982;Edwards et al., 1983;Sinensky and Logel, 1983), reflecting one of the highly regulated processes that prevent accumulation of these metabolites to toxic levels.Similar to other proteins of the MVA pathway (Horton et al., 2002), HMGR is controlled also at the transcriptional level by the sterol regulatory element-binding protein (SREBP)-2, which binds to the promoter of the HMGR gene and activates transcription when demands for MVA-derived products increase (Osborne et al., 1985;Vallett et al., 1996). Like its closely related SREBP-1a and SREBP-1c factors, SREBP-2 is synthesized as a large endoplasmic reticulum (ER)-bound precursor whose transcription activation domain must be released from the membrane to function in the nucleus. On increased demand for MVA-derived metabolites, the SREBP precursor is transported by COP-II vesicles to the Golgi, where it is sequentially cleaved at two sites by resident site-1 and site-2 proteases. The liberated transcriptionally active domain enters the nucleus and stimulates the transcription of target genes, including HMGR (Sakai et al., 1996;Nohturfft et al., 1998aNohturfft et al., , 2000. When sterols are abundant and demand for MVA-derived products declines, the transport of the SREBP precursor out from the ER is prevented and transcription ceases (Nohturfft et al., 1999(Nohturfft et al., , 2000. This metabolically regulated traffic of the SREBP precursors critically depends on SREBP cleavage-activating protein (SCAP), a membrane protein with eight transmembranes spans (TMs), which tightly associates with the SREBP precursors and enables the packaging of both proteins in the COP-II vesicles and their transport from the ER to the Golgi Sakai et al., 1997;Nohturfft et al., 1998b Feramisco et al., 2004). This sterol-stimulated binding to Insig(s) masks the transport signal in SCAP and abrogates i...

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“…The membrane protein CFTR has relatively large cytosolic domains that are monitored by at least two checkpoints located on the cytosolic side of the ER membrane (Younger et al, 2006). Lumenal proteins and membrane proteins with relatively large lumenal domains are monitored by quality-control machinery located in the ER lumen (Huyer et al, 2004;Vashist and Ng, 2004). The glycosylation status of these proteins provides cues as to the progression of folding This article was published online ahead of print in MBC in Press (http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E07-07-0674) on April 9, 2008.…”

Section: Introductionmentioning

confidence: 99%

ERdj4 and ERdj5 Are Required for Endoplasmic Reticulum-associated Protein Degradation of Misfolded Surfactant Protein C

Dong

Bridges

Apsley

et al. 2008

MBoC

144

171

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Mutations in the SFTPC gene associated with interstitial lung disease in human patients result in misfolding, endoplasmic reticulum (ER) retention, and degradation of the encoded surfactant protein C (SP-C) proprotein. In this study, genes specifically induced in response to transient expression of two disease-associated mutations were identified by microarray analyses. Immunoglobulin heavy chain binding protein (BiP) and two heat shock protein 40 family members, endoplasmic reticulum-localized DnaJ homologues ERdj4 and ERdj5, were significantly elevated and exhibited prolonged and specific association with the misfolded proprotein; in contrast, ERdj3 interacted with BiP, but it did not associate with either wild-type or mutant SP-C. Misfolded SP-C, ERdj4, and ERdj5 coprecipitated with p97/VCP indicating that the cochaperones remain associated with the misfolded proprotein until it is dislocated to the cytosol. Knockdown of ERdj4 and ERdj5 expression increased ER retention and inhibited degradation of misfolded SP-C, but it had little effect on the wild-type protein. Transient expression of ERdj4 and ERdj5 in X-box binding protein 1 ؊/؊ mouse embryonic fibroblasts substantially restored rapid degradation of mutant SP-C proprotein, whereas transfection of HPD mutants failed to rescue SP-C endoplasmic reticulum-associated protein degradation. ERdj4 and ERdj5 promote turnover of misfolded SP-C and this activity is dependent on their ability to stimulate BiP ATPase activity.

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Distinct Machinery Is Required in Saccharomyces cerevisiae for the Endoplasmic Reticulum-associated Degradation of a Multispanning Membrane Protein and a Soluble Luminal Protein

Cited by 251 publications

References 74 publications

Inositol Deacylation by Bst1p Is Required for the Quality Control of Glycosylphosphatidylinositol-anchored Proteins

Inositol Deacylation by Bst1p Is Required for the Quality Control of Glycosylphosphatidylinositol-anchored Proteins

Dislocation of HMG-CoA Reductase and Insig-1, Two Polytopic Endoplasmic Reticulum Proteins, En Route to Proteasomal Degradation

ERdj4 and ERdj5 Are Required for Endoplasmic Reticulum-associated Protein Degradation of Misfolded Surfactant Protein C

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