We have discovered 2 ubiquitin sorting receptors (Ub-sorting receptors) that sort ubiquitinated membrane proteins (Ub-cargo) for degradation in the lysosome. One is the GGA coat protein, which appears to bind Ubcargo at the TGN and incorporate it into vesicles targeted for delivery to the endosome. The other is a complex between Vps27 and Hse1 (aka Mrs and STAM1/2 in animal cells), which recognizes Ub-cargo at the endosome and promotes its entry into luminal vesicles of multivesicular endosomes (MVB). This proposal aims to understand how these receptors work in relation to other putative Ub-sorting receptors and how they coordinate the activity of Ub ligases and Ub-peptidases that may alter the ubiquitination status of cargo. We will examine the molecular mechanisms that control the activity of this machinery, in large part by analyzing the function of various interactions between this machinery and other proteins. The Vps27-Hse1 complex associates with Ub ligases and peptidases, clathrin, Coatamer and other proteins, as well as the ESCRT-I complex that also binds Ub and participates in MVB biogenesis. We will determine what the functional roles of these interactions are and how the Vps27-Hse1 Ub-sorting function of Vps27- Hse1 is coordinated with other putative Ub-sorting complexes is such as ESCRT-I. We will also determine what other proteins work with Gga proteins to effect Ub-dependent sorting at the TGN by testing the potential of a variety of candidate proteins and conducting genetic screens to identify genes that operate in this pathway.
| Krishnamani, Venkatramanan; Peterson, Tabitha A; Piper, Robert C et al. (2018) Informatic Analysis of Sequence Data from Batch Yeast 2-Hybrid Screens. J Vis Exp : |
| Peterson, Tabitha A; Stamnes, Mark A; Piper, Robert C (2018) A Yeast 2-Hybrid Screen in Batch to Compare Protein Interactions. J Vis Exp : |
| Xu, Peng; Hankins, Hannah M; MacDonald, Chris et al. (2017) COPI mediates recycling of an exocytic SNARE by recognition of a ubiquitin sorting signal. Elife 6: |
| MacDonald, Chris; Piper, Robert C (2017) Genetic dissection of early endosomal recycling highlights a TORC1-independent role for Rag GTPases. J Cell Biol 216:3275-3290 |
| MacDonald, Chris; Winistorfer, Stanley; Pope, Robert M et al. (2017) Enzyme reversal to explore the function of yeast E3 ubiquitin-ligases. Traffic 18:465-484 |
| Pashkova, Natasha; Peterson, Tabitha A; Krishnamani, Venkatramanan et al. (2016) DEEPN as an Approach for Batch Processing of Yeast 2-Hybrid Interactions. Cell Rep 17:303-315 |
| MacDonald, Chris; Piper, Robert C (2016) Cell surface recycling in yeast: mechanisms and machineries. Biochem Soc Trans 44:474-8 |
| MacDonald, Chris; Stamnes, Mark A; Katzmann, David J et al. (2015) Tetraspan cargo adaptors usher GPI-anchored proteins into multivesicular bodies. Cell Cycle 14:3673-8 |
| MacDonald, Chris; Payne, Johanna A; Aboian, Mariam et al. (2015) A family of tetraspans organizes cargo for sorting into multivesicular bodies. Dev Cell 33:328-42 |
| Peterson, Tabitha A; Yu, Liping; Piper, Robert C (2015) Backbone and side-chain NMR assignments for the C-terminal domain of mammalian Vps28. Biomol NMR Assign 9:21-4 |
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