Geldanamycins trigger a novel Ron degradative pathway, hampering oncogenic signaling

Serena Germano, Davide Barberis, Massimo M. Santoro, Lorenza Penengo, Ami Citri, Yosef Yarden, Giovanni Gaudino*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Ron, the tyrosine kinase receptor for macrophage-stimulating protein is responsible for proliferation and migration of cells from different tissues. Ron can acquire oncogenic potential by single point mutations in the kinase domain, and dysregulated Ron signaling has been involved in the development of different human cancers.Wehave previously shown that ligand-activated Ron recruits the negative regulator c-Cbl, which mediates its ubiquitylation and degradation. Here we report that Ron is ubiquitylated also by the U-box E3 ligase C-terminal Hsc70-interacting protein (CHIP), recruited via chaperone intermediates Hsp90 and Hsc70. Gene silencing shows that CHIP activity is necessary to mediate Ron degradation upon cell treatment with Hsp90 inhibitors geldanamycins. The oncogenic RonM1254T receptor escapes from c-Cbl negative regulation but retains a strong association with CHIP. This constitutively active mutant of Ron displays increased sensitivity to geldanamycins, enhanced physical interaction with Hsp90, and more rapid degradation rate. Cell growth and migration, as well as the transforming potential evoked by RonM1254T, are abrogated upon Hsp90 inhibition. These data highlight a novel mechanism for Ron degradation and propose Hsp90 antagonists like geldanamycins as suitable pharmacological agents for therapy of cancers where altered Ron signaling is involved.

Original languageAmerican English
Pages (from-to)21710-21719
Number of pages10
JournalJournal of Biological Chemistry
Issue number31
StatePublished - 4 Aug 2006
Externally publishedYes


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