Loss of BiP/GRP78 function blocks translocation of secretory proteins in yeast.

Vogel, Joseph P.; Misra, Leanne M.; Rose, Mark D.

doi:10.1083/jcb.110.6.1885

Cited by 428 publications

(311 citation statements)

References 48 publications

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“…We also observed accumulation of an unglycosylated form of CPY only in the type A mutant cells (unpublished data). These findings are consistent with previous reports (Vogel et al, 1990;Sanders et al, 1992) and suggest that type A and type S mutants correspond to the class I and class II kar2 mutants, respectively, defined by Brodsky and Rose (1997), based on their phenotypes. These observations strongly suggest that protein translocation into the ER is blocked only in the type A mutant strains.…”

Section: Discussionsupporting

confidence: 82%

Section: Impaired Association and Dissociation Of Kar2 And Ire1 In Kamentioning

confidence: 99%

“…Because KAR2 is essential for viability, studies of its physiological functions have been performed primarily using conditional lethal kar2 alleles. When cultured at the restrictive temperature, some of the temperature-sensitive kar2 mutant strains exhibit a block in the translocation of secretory proteins into the ER (Vogel et al, 1990;Sanders et al, 1992;Brodsky et al, 1995). Several molecular mechanisms have been proposed to explain the function of Kar2 in the protein translocation machinery (Hamman et al, 1998;Matlack et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

“…Anti-HA Western blot analysis of the cell lysates indicated that Ire1-HA was expressed at similar levels in all of the kar2 mutant and control wild-type strains (Figure 3, uppermost panel). The precursor form of Kar2 (pre-Kar2) was detected in lysates from the type A mutant cells by anti-Kar2 Western blotting (Figure 3, second panel, lanes 4 -9), suggesting that protein translocation is impaired in these cells (Vogel et al, 1990).The cell lysates were next subjected to anti-HA immunoprecipitation. Anti-HA Western blot analysis of the immunoprecipitates showed that nearly equal amounts of Ire1-HA were immunoprecipitated from each lysate (Figure 3, found to be complexed with Ire1-HA (Figure 3, lowest panel, lanes 2 and 12).…”

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confidence: 99%

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Genetic Evidence for a Role of BiP/Kar2 That Regulates Ire1 in Response to Accumulation of Unfolded Proteins

Kimata

Shimizu

Abe

et al. 2003

MBoC

189

177

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In the unfolded protein response (UPR) signaling pathway, accumulation of unfolded proteins in the endoplasmic reticulum (ER) activates a transmembrane kinase/ribonuclease Ire1, which causes the transcriptional induction of ER-resident chaperones, including BiP/Kar2. It was previously hypothesized that BiP/Kar2 plays a direct role in the signaling mechanism. In this model, association of BiP/Kar2 with Ire1 represses the UPR pathway while under conditions of ER stress, BiP/Kar2 dissociation leads to activation. To test this model, we analyzed five temperaturesensitive alleles of the yeast KAR2 gene. When cells carrying a mutation in the Kar2 substratebinding domain were incubated at the restrictive temperature, association of Kar2 to Ire1 was disrupted, and the UPR pathway was activated even in the absence of extrinsic ER stress. Conversely, cells carrying a mutation in the Kar2 ATPase domain, in which Kar2 poorly dissociated from Ire1 even in the presence of tunicamycin, a potent inducer of ER stress, were unable to activate the pathway. Our findings provide strong evidence in support of BiP/Kar2-dependent Ire1 regulation model and suggest that Ire1 associates with Kar2 as a chaperone substrate. We speculate that recognition of unfolded proteins is based on their competition with Ire1 for binding with BiP/Kar2. INTRODUCTIONAccumulation of unfolded proteins in the endoplasmic reticulum (ER) results in the transcriptional induction of various genes including those encoding ER-resident chaperones and folding enzymes. This cellular mechanism is called the unfolded protein response (UPR), and several important features of the UPR signaling pathway have been revealed initially through studies in the budding yeast Saccharomyces cerevisiae. Yeast Ire1 is a 1115-amino acid transmembrane protein that transmits the unfolded protein signal across the ER membrane (Cox et al., 1993;Mori et al., 1993). The cytoplasmic domain (C-terminal half) of Ire1 possesses both serine/threonine kinase and site-specific endoribonuclease activities Sidrauski and Walter, 1997). Ire1 dimerizes in response to the accumulation of unfolded proteins, resulting in its trans-autophosphorylation and activation (Shamu and Walter, 1996;Welihinda and Kaufman, 1996). Activated Ire1 in turn promotes splicing of HAC1 precursor mRNA to produce the mature form (Cox and Walter, 1996;Sidrauski and Walter, 1997), which is effectively translated into a functional transcription factor (Mori et al., 2000;Ruegsegger et al., 2001). Mature form of Hac1 efficiently induces transcription of UPR target genes containing the UPR element (UPRE) in their promoter region (Mori et al., 1992;Kohno et al., 1993).In mammalian cells, accumulation of unfolded proteins initiates signaling from the ER via more complicated pathways. Two homologues of Ire1, Ire1␣ and Ire1␤, have been identified (Tirasophon et al., 1998;Wang et al., 1998;Iwawaki et al., 2001). According to recent reports (Yoshida et al., 2001;Calfon et al., 2002), IRE1 functions to promote splicing of an mRNA encoding ...

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Section: Discussionsupporting

confidence: 82%

Section: Impaired Association and Dissociation Of Kar2 And Ire1 In Kamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Genetic Evidence for a Role of BiP/Kar2 That Regulates Ire1 in Response to Accumulation of Unfolded Proteins

Kimata

Shimizu

Abe

et al. 2003

MBoC

189

177

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“…Genes encoding homologues of mammalian SRP or SRP receptor components have been identified (Felici et al, 1989;Hann et al, 1989Hann et al, , 1992Amaya et al, 1990;Ogg et al, 1992;Stirling and Hewitt, 1992), and depletion of these homologs causes a translocation defect in vivo (Amaya and Nakano, 1991;Hann and Walter, 1991;Ogg et al, 1992;Stirling and Hewitt, 1992). Mutations in four essential genes (SEC61, SEC62, SEC63, and KAR2) are associated with translocation defects Schekman, 1987, 1989;Toyn et al, 1988;Sadler et al, 1989;Vogel et al, 1990;, and genetic and biochemical evidence indicates physical interactions between their protein products Deshaies et al, 1991;Scidmore, Okamura, and Rose, unpublished data). Sec6lp, Sec62p, and Kar2p can be cross-linked to translocating polypeptide chains in yeast ER membranes (Musch et al, 1992;Sanders et al, 1992), suggesting that they comprise components of a common translocation apparatus.…”

Section: Introductionmentioning

confidence: 99%

Suppression of a sec63 mutation identifies a novel component of the yeast endoplasmic reticulum translocation apparatus.

Kurihara

Silver

1993

MBoC

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Mutations in the SEC63 gene are associated with defects in protein translocation into the endoplasmic reticulum (ER) as well as in nuclear protein localization in Saccharomyces cerevisiae. To identify proteins that might interact and/or function with SEC63p, we cloned a high copy suppressor (HSS1) of the temperature-sensitive lethal phenotype of the sec63-101 mutant. HSS1 is an allele-specific sec63 suppressor that encodes an integral ER membrane glycoprotein of 206 amino acids with the N-terminus in the ER lumen and C-terminal region in the cytoplasm. Haploid strains disrupted for HSS1 are temperature-sensitive for growth and accumulate precursor forms of Kar2p and invertase. The HSS1 null allele is synthetically lethal in combination with mutations affecting ER translocation. We propose that HSSlp is important for ER translocation and interacts with previously identified components of the yeast translocation apparatus. HSS1 is identical to SEC66, which encodes a glycoprotein complexed with SEC62p and SEC63p.

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Inducible Membranes in Yeast: Relation to the Unfolded-Protein-Response Pathway

Menzel

Vogel

Kärgel

et al. 1997

Yeast

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Overproduction of an endoplasmic reticulum (ER)‐resident membrane protein (cytochrome P450 52A3) and of a secretory protein (invertase) was used to study the regulation of the luminal ER protein Kar2p under conditions that lead to ER proliferation and secretory overload, respectively. In both cases we found (i) a significant increase of Kar2 protein and mRNA levels, (ii) a transcriptional regulation based on the function of the 22 bp unfolded‐protein‐response element of the KAR2 promoter and (iii) an essential role of the transmembrane kinase Ire1p for upregulation of KAR2 gene expression. These results show that the same mechanism operates when KAR2 induction is triggered by overproduction of cytochrome P450 or invertase and that this mechanism shares the known features of the unfolded‐protein‐response pathway. Disruption of the IRE1 gene resulted in a marked decrease of the invertase protein levels produced. In contrast, a functional IRE1 gene was not required to reach high‐level production of the integral membrane protein cytochrome P450 52A3. Moreover, IRE1 gene disruption did not prevent P450‐induced ER proliferation. We suggest that Ire1p‐mediated KAR2 induction is, in the case of cytochrome P450 52A3 overproduction, a process which follows on ER proliferation, thereby monitoring the increase of ER size and adjusting the level of Kar2p accordingly. © 1997 John Wiley & Sons, Ltd.

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Loss of BiP/GRP78 function blocks translocation of secretory proteins in yeast.

Cited by 428 publications

References 48 publications

Genetic Evidence for a Role of BiP/Kar2 That Regulates Ire1 in Response to Accumulation of Unfolded Proteins

Genetic Evidence for a Role of BiP/Kar2 That Regulates Ire1 in Response to Accumulation of Unfolded Proteins

Suppression of a sec63 mutation identifies a novel component of the yeast endoplasmic reticulum translocation apparatus.

Inducible Membranes in Yeast: Relation to the Unfolded-Protein-Response Pathway

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