TSG101/mammalian VPS23 and mammalian VPS28 interact directly and are recruited to VPS4-induced endosomes.
Class E vacuolar protein sorting (vps) proteins are required for appropriate sorting of receptors within the yeast endocytic pathway, and most probably function in the biogenesis of multivesicular bodies. We have identified the mammalian orthologue of Vps28p as a 221- amino acid cytosolic protein that interacts with TSG101/mammalian VPS23 to form part of a multiprotein complex. Co-immunoprecipitation and cross-linking experiments demonstrated that hVPS28 and TSG101 interact directly and that binding requires structural information within the conserved C-terminal portion of TSG101. TSG101 and hVPS28 are predominantly cytosolic. However, when endosomal vacuolization was induced by the expression of a dominant-negative mutant of another class E vps protein, human VPS4, a portion of both TSG101 and hVPS28 translocated to the surface of these vacuoles. We conclude that TSG101 and its interacting components are directly involved in endosomal sorting.
Bishop
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School of Biological Sciences, University of Manchester, 2.205 Stopford Bldg., Oxford Rd., Manchester M13 9PT, United Kingdom.
Woodman
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P
D000251:Adenosine Triphosphatases; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004247:DNA; D004268:DNA-Binding Proteins / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport; D011992:Endosomes / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011485:Protein Binding; D017433:Protein Structure, Secondary; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism*; D033921:Vesicular Transport Proteins; D000099177:Tsg101 Protein
D000251:Adenosine Triphosphatases; D002352:Carrier Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D033921:Vesicular Transport Proteins; D000099177:Tsg101 Protein; C102954:VPS28 protein, S cerevisiae; C107528:VPS4 protein, S cerevisiae