SORTING AND TRANSPORT OF MEMBRANE PROTEINS

Summary

Principal Investigator: TOM HALL STEVENS
Affiliation: University of Oregon
Country: USA
Abstract: The work is aimed at understanding the sorting and transport of membrane proteins to the yeast lysosome-like vacuole. The simple eukaryote yeast will be used as a model eukaryotic sorting system, since the secretory and vacuole assembly pathways are very similar to the pathways in animal cells. Studies in yeast offer a unique opportunity to investigate the complex processes involved in membrane protein sorting and transport by taking advantage of the ability to exploit the powerful genetic approaches available in yeast. It also appears likely that the basic cellular functions that facilitate sorting of vacuolar/lysosomal membrane proteins will be conserved across all eukaryotic cells. Yeast mutants that mislocalize the vacuolar membrane protein dipeptidyl amino-peptidase (DPAP-B) will be obtained by exploiting a newly developed selection procedure. These mutants will be screened biochemically and by immunogold labeling for the secretion of a large number of soluble and membrane-bound vacuolar proteins. In addition, a major effort will be made towards identifying the vacuolar sorting and transport signals present on the membrane protein DPAP-B. Mutations in the DPAP-B structural gene will be generated and those resulting in missorting of enzymatically active DPAP-B will be identified with the DPAP-B mislocalization selection procedure. The structural genes of the two largest subunits of the yeast vacuolar membrane H+-translocating ATPase will be cloned using the Lambdagtll yeast library. Mutations will be constructed in these genes to elucidate the role of this H+-ATPase in acidification of the vacuole. These mutations will also permit an analysis of the role of acidification in the sorting of newly synthesized vacuolar hydrolases, in fluid-phase and receptor-mediated endocytosis, and in the function of the vacuole. The biosynthesis, assembly, targeting and transport of this vacuolar multi-subunit membrane-bound H+-ATPase complex will be investigated in an effort to understand the relationship between the synthesis and assembly of the subunits and their transport to the vacuole. These studies are likely to increase our basic understanding of diseases that result from missorting of lysosomal hydrolases such as Mucolipidosis II and III and other lysosomal storage diseases.
Funding Period: 1987-04-01 - 1992-03-31
more information: NIH RePORT

Top Publications

  1. ncbi Protein transport from the late Golgi to the vacuole in the yeast Saccharomyces cerevisiae
    Katherine Bowers
    Cambridge Institute for Medical Research and Department of Clinical, Biochemistry, University of Cambridge, Addenbrooke s Hospital, Hills Road, Cambridge CB2 2XY, UK
    Biochim Biophys Acta 1744:438-54. 2005
  2. ncbi Vma9p (subunit e) is an integral membrane V0 subunit of the yeast V-ATPase
    Mark A Compton
    Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 1229, USA
    J Biol Chem 281:15312-9. 2006
  3. ncbi PKR1 encodes an assembly factor for the yeast V-type ATPase
    Sandra R Davis-Kaplan
    Division of Immunology and Cell Biology, Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132 2501, USA
    J Biol Chem 281:32025-35. 2006
  4. pmc Arabidopsis has two functional orthologs of the yeast V-ATPase assembly factor Vma21p
    Christoph Neubert
    Center for Plant Molecular Biology, ZMBP, University of Tubingen, Auf der Morgenstelle 1, 72076 Tubingen, Germany
    Traffic 9:1618-28. 2008
  5. pmc Functional characterization of the N-terminal domain of subunit H (Vma13p) of the yeast vacuolar ATPase
    Andrew R Flannery
    Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536 0812, USA
    J Biol Chem 283:29099-108. 2008
  6. pmc Voa1p functions in V-ATPase assembly in the yeast endoplasmic reticulum
    Margret Ryan
    Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
    Mol Biol Cell 19:5131-42. 2008

Detail Information

Publications6

  1. ncbi Protein transport from the late Golgi to the vacuole in the yeast Saccharomyces cerevisiae
    Katherine Bowers
    Cambridge Institute for Medical Research and Department of Clinical, Biochemistry, University of Cambridge, Addenbrooke s Hospital, Hills Road, Cambridge CB2 2XY, UK
    Biochim Biophys Acta 1744:438-54. 2005
    ..We will review the molecular mechanisms of protein targeting from the late Golgi to endosomes and to the vacuole (the equivalent of the mammalian lysosome) of the budding yeast Saccharomyces cerevisiae...
  2. ncbi Vma9p (subunit e) is an integral membrane V0 subunit of the yeast V-ATPase
    Mark A Compton
    Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 1229, USA
    J Biol Chem 281:15312-9. 2006
    ..These results demonstrate that Vma9p is an integral membrane subunit of the yeast V-ATPase V0 subcomplex and suggest a model for the arrangement of polypeptides within the V0 subcomplex...
  3. ncbi PKR1 encodes an assembly factor for the yeast V-type ATPase
    Sandra R Davis-Kaplan
    Division of Immunology and Cell Biology, Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah 84132 2501, USA
    J Biol Chem 281:32025-35. 2006
    ..Our data indicate that Pkr1p functions together with the other V-ATPase assembly factors in the ER to efficiently assemble the V-ATPase membrane sector...
  4. pmc Arabidopsis has two functional orthologs of the yeast V-ATPase assembly factor Vma21p
    Christoph Neubert
    Center for Plant Molecular Biology, ZMBP, University of Tubingen, Auf der Morgenstelle 1, 72076 Tubingen, Germany
    Traffic 9:1618-28. 2008
    ..Moreover, VMA21p acts as a dedicated ER escort chaperone, a class of substrate-specific accessory proteins so far not identified in higher plants...
  5. pmc Functional characterization of the N-terminal domain of subunit H (Vma13p) of the yeast vacuolar ATPase
    Andrew R Flannery
    Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536 0812, USA
    J Biol Chem 283:29099-108. 2008
    ..These results suggest that the mammalian V-ATPase complexes with subunit H splice variant SFD-alpha or SFD-beta are likely to have different activities and may perform distinct cellular functions...
  6. pmc Voa1p functions in V-ATPase assembly in the yeast endoplasmic reticulum
    Margret Ryan
    Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
    Mol Biol Cell 19:5131-42. 2008
    ..Our results suggest Voa1p functions with Vma21p early in V(0) assembly in the ER, but then it dissociates before exit of the V(0)-Vma21p complex from the ER for transport to the Golgi compartment...