USP9X Controls EGFR Fate by Deubiquitinating the Endocytic Adaptor Eps15

• Published in: Current biology 2016-01, Vol.26 (2), p.173-183
• Main Authors: Savio, Michol Giovanna, Wollscheid, Nadine, Cavallaro, Elena, Algisi, Veronica, Di Fiore, Pier Paolo, Sigismund, Sara, Maspero, Elena, Polo, Simona
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Cell Line, Tumor; deubiquitinating enzymes; EGFR; Endocytosis - physiology; Endosomes - metabolism; Epidermal Growth Factor - metabolism; Eps15; ErbB Receptors - metabolism; Humans; Lysosomes - metabolism; Protein Processing, Post-Translational - physiology; Protein Transport - physiology; ubiquitin; Ubiquitin Thiolesterase - metabolism; USP9X
• ISSN: 0960-9822; 1879-0445; 1879-0445
• DOI: 10.1016/j.cub.2015.11.050

Following activation by its cognate ligand(s), the epidermal growth factor receptor (EGFR) is rapidly routed to the lysosome for degradation in a ubiquitination-dependent fashion. This pathway represents the major mechanism of long-term attenuation of EGFR signaling, and its deregulation is a significant feature in different types of cancers. Here we demonstrate, through a systematic RNAi-based approach, that several deubiquitinating (DUB) enzymes extend or decrease EGFR half-life upon EGF stimulation. We focus on USP9X, whose depletion severely affects EGFR turnover, interfering with its internalization and trafficking. We identify the endocytic protein Eps15 as one of the critical substrates of USP9X, and we map the Eps15 ubiquitination sites. We found that Eps15 monoubiquitination occurs already at minimal dose of EGF stimulation and is essential for EGFR internalization. Overall, our findings identify USP9X as a novel regulator of EGFR endocytosis and suggest a model whereby cycles of ubiquitination and deubiquitination events on endocytic accessory proteins may regulate the internalization and trafficking of the EGFR toward the lysosomes. [Display omitted] •Fifteen DUBs have impact on EGFR fate•USP9X regulates EGFR internalization and trafficking•The endocytic protein Eps15 is a relevant target of USP9X•Monoubiquitination of Eps15 is required for EGFR internalization Savio et al. undertook a siRNA screen to find 18 DUBs that affect EGFR degradation. They focus on USP9X, whose depletion significantly delayed EGFR internalization and trafficking. USP9X counteracts monoubiquitination of Eps15 that occurs at minimal EGF dose and is critical for EGFR internalization.