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| Mol. Biol. Cell May (2007); 18(5):1781-9 | |
| Direct binding to Rsp5p regulates ubiquitination-independent vacuolar transport of Sna3p- | |
| Watson H, Bonifacino JS | |
| Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA- | |
| Abstract: The sorting of integral membrane proteins such as carboxypeptidase S -Cps1p- into the luminal vesicles of multivesicular bodies -MVBs- in Saccharomyces cerevisiae requires ubiquitination of their cytosolic domains by the ubiquitin ligases Rsp5p and-or Tul1p- An exception is Sna3p, which does not require ubiquitination for entry into MVBs- The mechanism underlying this ubiquitination-independent MVB sorting pathway has not yet been characterized- Here, we show that Sna3p sorting into the MVB pathway depends on a direct interaction between a PPAY motif within its C-terminal cytosolic tail and the WW domains of Rsp5p- Disruption of this interaction inhibits vacuolar targeting of Sna3p and causes its accumulation in a compartment that overlaps only partially with MVBs- Surprisingly, Sna3p does require a functional ubiquitin-ligase HECT domain within Rsp5p; however, the dependence of Sna3p on HECT domain activity is distinct from that of Cps1p- Last, we show that Sna3p requires neither Tul1p nor the transmembrane adaptor protein Bsd2p for its MVB sorting- Our data demonstrate that Sna3p follows a novel ubiquitination-independent, but Rsp5p-mediated, sorting pathway to the vacuole- | |
| [PUBMED: 17332499] |   |
| Copyright © 2009, Tyers Lab, The Samuel Lunenfeld Research Institute, Mount Sinai Hospital, All Rights Reserved. |
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| BioGRID: A General Repository for Interaction Datasets. Chris Stark, Bobby-Joe Breitkreutz, Teresa Reguly, Lorrie Boucher, Ashton Breitkreutz, Mike Tyers. Nucleic Acids Res. Jan 1;34:D535-9. |