Erp1p and Erp2p, Partners for Emp24p and Erv25p in a Yeast p24 Complex

Marzioch, Martina; Henthorn, Debbie C.; Herrmann, Johannes M.; Wilson, R.; Thomas, David Y.; Bergeron, John J.M.; Solari, Roberto; Rowley, Adele

doi:10.1091/mbc.10.6.1923

Cited by 177 publications

(264 citation statements)

References 36 publications

(74 reference statements)

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“…We also monitored the expression levels of the Emp24p and Erv25p proteins. As observed previously (8,14) their expression was interdependent such that emp24⌬ and erv25⌬ reduced the levels of Erv25p and Emp24p, respectively. Near wild-type levels were observed in the ⌬24-EME strain, and the other truncation or chimeric proteins were expressed at variably lower levels.…”

Section: Resultssupporting

confidence: 77%

“…Based on these and other findings, the p24 proteins have been proposed to act as structural components of vesicles (10), as cargo receptors (11), as negative regulators of vesicle budding (7) or to establish specialized subdomains on organellar membranes (12,13). There are eight p24 proteins in yeast encoded by EMP24, ERV25, and ERP1-ERP6 (14). Deletion of EMP24 and/or ERV25 produce the strongest phenotypes with regard to the transport and sorting defects; however, deletion of the ERP1 and ERP2 genes also display similar but weaker phenotypes.…”

mentioning

confidence: 99%

“…Deletion of EMP24 and/or ERV25 produce the strongest phenotypes with regard to the transport and sorting defects; however, deletion of the ERP1 and ERP2 genes also display similar but weaker phenotypes. Indeed, evidence suggests that Emp24p, Erv25p, Erp1p, and Erp2p function in a heteromeric complex (8,14). There are no apparent phenotypes associated with deletion of the ERP3-ERP6 genes.…”

mentioning

confidence: 99%

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Distinct Roles for the Cytoplasmic Tail Sequences of Emp24p and Erv25p in Transport between the Endoplasmic Reticulum and Golgi Complex

Belden

Barlowe

2001

Journal of Biological Chemistry

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Heteromeric complexes of p24 proteins cycle between early compartments of the secretory pathway and are required for efficient protein sorting. Here we investigated the role of cytoplasmically exposed tail sequences on two p24 proteins, Emp24p and Erv25p, in directing their movement and subcellular location in yeast. Studies on a series of deletion and chimeric Emp24p-Erv25p proteins indicated that the tail sequences impart distinct functional properties that were partially redundant but not entirely interchangeable. Export of an Emp24p-Erv25p complex from the endoplasmic reticulum (ER) did not depend on two other associated p24 proteins, Erp1 and Erp2p. To examine interactions between the Emp24p and Erv25p tail sequences with the COPI and COPII coat proteins, binding experiments with immobilized tail peptides and coat proteins were performed. The Emp24p and Erv25p tail sequences bound the Sec13p/Sec31p subunit of the COPII coat (K d ϳ100 M), and binding depended on a pair of aromatic residues found in both tail sequences. COPI subunits also bound to these Emp24p and Erv25p peptides; however, the Erv25p tail sequence, which contains a dilysine motif, bound COPI more efficiently. These results suggest that both the Emp24p and Erv25p cytoplasmic sequences contain a di-aromatic motif that binds subunits of the COPII coat and promotes export from the ER. The Erv25p tail sequence binds COPI and is responsible for returning this complex to the ER.The secretory pathway in eukaryotic cells consists of a series of membrane-bound compartments that modify, sort and transport secretory cargo. Transport through this pathway depends on coat protein complexes that form vesicles and select specific cargo molecules for incorporation into vesicles. Current models suggest that transport between organelles is bi-directional, such that organellar constituents are recycled as secretory cargo advances. With regard to transport through the early secretory pathway, coat protein complex II (COPII) 1 catalyzes anterograde transport between the ER and Golgi whereas coat protein complex I (COPI) acts in retrograde traffic between these compartments (1). In addition to coat-dependent export of secretory cargo from the ER, retrieval (2) and retention (3) mechanisms operate to maintain overall compartmental organization.A related group of integral membrane proteins, referred to as the p24 family, are thought to act in concert with COPI and COPII to sort proteins during transport through the early secretory pathway. Initially identified on ER membranes (4) and subsequently detected as abundant proteins on COPI-and COPII-coated vesicles (5, 6), the function of p24 proteins in sorting remains unclear. In yeast strains lacking certain p24 members, some secretory proteins accumulate in the ER (e.g. invertase and the GPI-anchored protein Gas1p), while ER resident proteins that contain an HDEL retrieval motif are secreted and the unfolded protein response pathway is activated (6 -9). Based on these and other findings, the p24 proteins have been propo...

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Section: Resultssupporting

confidence: 77%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Distinct Roles for the Cytoplasmic Tail Sequences of Emp24p and Erv25p in Transport between the Endoplasmic Reticulum and Golgi Complex

Belden

Barlowe

2001

Journal of Biological Chemistry

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“…39 and 40). ERGIC-53 exists as dimers and hexamers (39), whereas p24 complexes are heterotetramers (41,42). If the exit of MHC class I molecules involves interactions with specific cargo receptors, and if these have the properties of known cargo receptors, then HLA-A2 molecules should be clustered for export.…”

Section: Discussionmentioning

confidence: 99%

Clustering of Peptide-Loaded MHC Class I Molecules for Endoplasmic Reticulum Export Imaged by Fluorescence Resonance Energy Transfer

Pentcheva

Edidin

2001

The Journal of Immunology

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Fluorescence resonance energy transfer between cyan fluorescent protein- and yellow fluorescent protein-tagged MHC class I molecules reports on their spatial organization during assembly and export from the endoplasmic reticulum (ER). A fraction of MHC class I molecules is clustered in the ER at steady state. Contrary to expectations from biochemical models, this fraction is not bound to the TAP. Instead, it appears that MHC class I molecules cluster after peptide loading. This clustering points toward a novel step involved in the selective export of peptide-loaded MHC class I molecules from the ER. Consistent with this model, we detected clusters of wild-type HLA-A2 molecules and of mutant A2-T134K molecules that cannot bind TAP, but HLA-A2 did not detectably cluster with A2-T134K at steady state. Lactacystin treatment disrupted the HLA-A2 clusters, but had no effect on the A2-T134K clusters. However, when cells were fed peptides with high affinity for HLA-A2, mixed clusters containing both HLA-A2 and A2-T134K were detected.

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“…These proteins represent a wide diversity of functions, such as Rgt2p and Hxt12p involved in glucose sensing and transport (36, 37), the lipid biosynthesis proteins Ole1p and Ipt1p (38,39), and the endosomal, lipid-translocation-associated protein Cdc50p (40). In particular, overexpression of the multidrug transporter Sge1p (41), the COPII vesicle transport protein Erp1p (42), and the functionally unclassified protein Ycl045cp induces hypertolerance to paraquat.…”

Section: Identification Of Membrane Proteins Conferring Stress Resistmentioning

confidence: 99%

Phenotypic effects of membrane protein overexpression in Saccharomyces cerevisiae

Österberg

Kim

Warringer

et al. 2006

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

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Large-scale protein overexpression phenotype screens provide an important complement to the more common gene knockout screens. Here, we have targeted the so far poorly understood Saccharomyces cerevisiae membrane proteome and report growth phenotypes for a strain collection overexpressing Ϸ600 C-terminally tagged integral membrane proteins grown both under normal and three different stress conditions. Although overexpression of most membrane proteins reduce the growth rate in synthetic defined medium, we identify a large number of proteins that, when overexpressed, confer specific resistance to various stress conditions. Our data suggest that regulation of glycosylphosphatidylinositol anchor biosynthesis and the Na ؉ ͞K ؉ homeostasis system constitute major downstream targets of the yeast PKA͞RAS pathway and point to a possible connection between the early secretory pathway and the cells' response to oxidative stress. We also have quantified the expression levels for >550 membrane proteins, facilitating the choice of well expressing proteins for future functional and structural studies.caffeine ͉ paraquat ͉ salt tolerance ͉ yeast

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Erp1p and Erp2p, Partners for Emp24p and Erv25p in a Yeast p24 Complex

Cited by 177 publications

References 36 publications

Distinct Roles for the Cytoplasmic Tail Sequences of Emp24p and Erv25p in Transport between the Endoplasmic Reticulum and Golgi Complex

Distinct Roles for the Cytoplasmic Tail Sequences of Emp24p and Erv25p in Transport between the Endoplasmic Reticulum and Golgi Complex

Clustering of Peptide-Loaded MHC Class I Molecules for Endoplasmic Reticulum Export Imaged by Fluorescence Resonance Energy Transfer

Phenotypic effects of membrane protein overexpression in Saccharomyces cerevisiae

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