| First Author | Yamashita Y | Year | 2008 |
| Journal | J Cell Sci | Volume | 121 |
| Issue | Pt 10 | Pages | 1727-38 |
| PubMed ID | 18445679 | Mgi Jnum | J:139788 |
| Mgi Id | MGI:3810051 | Doi | 10.1242/jcs.024455 |
| Citation | Yamashita Y, et al. (2008) Ubiquitin-independent binding of Hrs mediates endosomal sorting of the interleukin-2 receptor beta-chain. J Cell Sci 121(Pt 10):1727-38 |
| abstractText | Several lines of evidence have revealed that ubiquitylation of membrane proteins serves as a signal for endosomal sorting into lysosomes or lytic vacuoles. The hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) interacts with ubiquitylated cargoes through its ubiquitin-interacting-motif domain (UIM domain), and plays an essential early role in endosomal sorting. Here, we show that the C-terminal region of Hrs, which does not contain the UIM domain, can bind to interleukin-2 receptor beta (IL-2Rbeta). We found a direct interaction between bacterially expressed IL-2Rbeta and Hrs in GST pull-down assays, indicating that their binding is independent of ubiquitin. Trafficking and degradation assays revealed that, similarly to wild-type IL-2Rbeta, an IL-2Rbeta mutant lacking all the cytoplasmic lysine residues is sorted from Hrs-positive early endosomes to LAMP1-positive late endosomes, resulting in degradation of the receptor. By contrast, an IL-2Rbeta mutant lacking the Hrs-binding region passes through early endosomes and is mis-sorted to compartments positive for the transferrin receptor. The latter mutant exhibits attenuated degradation. Taken together, these results indicate that precise sorting of IL-2Rbeta from early to late endosomes is mediated by Hrs, a known sorting component of the ubiquitin-dependent machinery, in a manner that is independent of UIM-ubiquitin binding. |
