A two-tiered mechanism of EGFR inhibition by RALT/MIG6 via kinase suppression and receptor degradation

Yuri Frosi, Sergio Anastasi, Costanza Ballarò, Giulia Varsano, Loriana Castellani, Elena Maspero, Simona Polo, Stefano Alemà, Oreste Segatto

Research output: Contribution to journalArticlepeer-review

Abstract

Signaling by epidermal growth factor receptor (EGFR) must be controlled tightly because aberrant EGFR activity may cause cell transformation. Receptor-associated late transducer (RALT) is a feedback inhibitor of EGFR whose genetic ablation in the mouse causes phenotypes due to EGFR-driven excess cell proliferation. RALT inhibits EGFR catalytic activation by docking onto EGFR kinase domain. We report here an additional mechanism of EGFR suppression mediated by RALT, demonstrating that RALT-bound EGF receptors undergo endocytosis and eventual degradation into lysosomes. Moreover, RALT rescues the endocytic deficit of EGFR mutants unable to undergo either endocytosis (Dc214) or degradation (Y1045F) and mediates endocytosis via a domain distinct from that responsible for EGFR catalytic suppression. Consistent with providing a scaffolding function for endocytic proteins, RALT drives EGFR endocytosis by binding to AP-2 and Intersectins. These data suggest a model in which binding of RALT to EGFR integrates suppression of EGFR kinase with receptor endocytosis and degradation, leading to durable repression of EGFR signaling.

Original languageEnglish
Pages (from-to)557-571
Number of pages15
JournalJournal of Cell Biology
Volume189
Issue number3
DOIs
Publication statusPublished - May 3 2010

ASJC Scopus subject areas

  • Cell Biology

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