Yeast counterparts of subunits S5a and p58 (S3) of the human 26S proteasome are encoded by two multicopy suppressors of nin1-1.

Kominami, Kin‐ichiro; Okura, Naganari; Kawamura, M.; DeMartino, George N.; Slaughter, Clive A.; Shimbara, Naoki; Chung, Chin Ha; Fujimuro, Masahiro; Yokosawa, Hideyoshi; Shimizu, Yoshihisa; Tanahashi, Nobuyuki; Tanaka, Keiji; Toh‐e, Akio

doi:10.1091/mbc.8.1.171

Cited by 93 publications

(79 citation statements)

References 64 publications

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“…Compared with the well understood biochemistry of the ubiquitylation machinery and the molecular aspects of the proteasome, however, it is not completely clear yet how a targeted protein is delivered to the 26S proteasome; in particular, it has been puzzling how polyubiquitin chains are recognized by the proteasome. At least one component of the 19S proteasomal cap, Rpn10/S5a, seems capable of binding tightly to polyubiquitin (13,14), but it is not an essential gene in yeast, raising the possibility that other factors are involved (15,16). As we show in this paper, Dsk2p seems to be one of these previously unrecognized polyubiquitin-binding factors and uses its UbL and UBA domains to perform the recognition.…”

mentioning

confidence: 70%

Budding yeast Dsk2p is a polyubiquitin-binding protein that can interact with the proteasome

Funakoshi

Sasaki²,

Nishimoto³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

221

254

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Dsk2p from Saccharomyces cerevisiae belongs to the class of proteins that contain a ubiquitin-like (UbL) domain at the N terminus together with a ubiquitin-associated (UBA) domain at the C terminus. We show here that the C-terminal UBA domain of Dsk2p binds to K48-linked polyubiquitin chains, and the N-terminal UbL domain of Dsk2p interacts with the proteasome. Overexpression of Dsk2p caused the accumulation of large amounts of polyubiquitin, and extragenic suppressors of the Dsk2p-mediated lethality proved to be temperature-sensitive mutations in two proteasome subunits, rpn1 and pre2. K48-linked ubiquitin-dependent degradation was impaired by disruption of the DSK2 gene. These results indicate that Dsk2p is K48-linked polyubiquitinbinding protein and also interacts with the proteasome. We discuss a possible role of adaptor function of Dsk2p via its UbL and UBA domains in the ubiquitin-proteasome pathway.ubiquitin-related protein ͉ polyubiquitin adaptor ͉ UBA domain ͉ ubiquitin chains ͉ UbL domain

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mentioning

confidence: 70%

Budding yeast Dsk2p is a polyubiquitin-binding protein that can interact with the proteasome

Funakoshi

Sasaki²,

Nishimoto³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

221

254

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“…Data from analyses of yeast mutants suggest that the NIN1 gene is necessary for activation of Cdc28 kinase (yeast cyclin-dependent kinase, the key regulator of the eukaryotic cell cycle) (Kominami et al, 1995). The products of both NIN1 and SUN2 genes are considered to be subunits of the regulatory complex of the 26S proteasome (Kominami et al, 1995;Kominami, et al, 1997). However, the reported data are not sufficient to understand the function of the Sun2 protein.…”

Section: Discussionmentioning

confidence: 99%

“…The Dox-A2 protein is considered to be a component of DOX because a mutation of the Dox-A2 gene affects DOX function and causes the disappearance of one isoform. In contrast, two other proteins that share identity with the 21D7 protein, bovine p58, partially sequenced by DeMartino et al (1994), and Sacckaromyces cerevisiae Sun2 (Kawamura et al, 1996;Kominami et al, 1997), are subunits of a proteolytic enzyme, the 26s proteasome. This contradiction can be explained by the fact that in some organisms, phenol oxidases are activated by proteolysis (Wright, 1987).…”

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confidence: 99%

Plant 21D7 Protein, a Nuclear Antigen Associated with Cell Division, Is a Component of the 26S Proteasome

et al. 1997

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Previously, we cloned a carrot (Daucus carota L.) cDNA encoding a 45-kD protein, 21D7, located in the nuclei of proliferating cells. The 21D7 protein is similar to the partia1 sequence of a regulatory subunit of the bovine 26s proteasome, p58 (C. DeMartino, C.R. Moomaw, O.P. Zagnitko, R.J. Proske, M. Chu-Ping, S.J. Afendis, J.C. Swaffield, C.A. Slaughter [1994] J Biol Chem 269:20878-20884) and to the deduced sequence encoded by the Saccharomyces cerevisiae gene SUN2 (M. Kawamura, K. Kominami, J. Takeuchi, A. Toh-e [1996] MOI Cen Cenet 251 : 11 46-1 521). I n our work, the expression of plant 21 D7 cDNA rescued the yeast sun2 mutant. Fractionation of carrot and spinach (Spinacia oleracea L.) crude extracts showed that the 21 D7 protein sedimented with the active 26s proteasomes. The cessation of cell proliferation in carrot suspensions at the stationary phase caused 26s proteasome dissociation and, correspondingly, the 21 D7 protein sedimented together with the free regulatory complexes of the 26s proteasomes. Large-scale purification of carrot 26s proteasomes resulted i n coisolation of the 21 D 7 protein. Polyacrylamide gel electrophoresis under nondenaturing conditions showed that the 21 D7 protein had the same mobility as the 26s proteasome and that proteasome dissociation changed the mobility of the 21 D7 protein accordingly. We conclude that the 21D7 protein is a subunit of the plant 26s proteasome and that it probably belongs to the proteasome regulatory complex.Most molecular studies of the cell division cycle in higher plants are based on the cloning of plant homologs of yeast and animal genes that control the cell cycle progression. However, in a number of cases the association of a gene with cell division has been shown first in a plant system (eg. Kodama et al., 1991;Ito and Komamine, 1993). In one of these cases, immunochemical studies of somatic embryogenesis resulted in the identification of a 45-kD carrot (Daucus carota L.) antigen, named 21D7 after the

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“…Gas1*p was dramatically stabilized by the addition of MG-132 ( Figure 4E). In addition, the degradation of Gas1*p was significantly delayed in rpn3-1 and rpn12-1 proteasome mutant cells (Kominami et al, 1995(Kominami et al, , 1997 (Figure 4F), strongly suggesting that it is degraded by ERAD and subsequent proteasome-mediated degradation.…”

Section: Construction and Characterization Of Misfolded Gas1mentioning

confidence: 93%

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...

show abstract

Yeast counterparts of subunits S5a and p58 (S3) of the human 26S proteasome are encoded by two multicopy suppressors of nin1-1.

Cited by 93 publications

References 64 publications

Budding yeast Dsk2p is a polyubiquitin-binding protein that can interact with the proteasome

Budding yeast Dsk2p is a polyubiquitin-binding protein that can interact with the proteasome

Plant 21D7 Protein, a Nuclear Antigen Associated with Cell Division, Is a Component of the 26S Proteasome

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

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