The HSP90 inhibitor geldanamycin perturbs endosomal structure and drives recycling ErbB2 and transferrin to modified MVBs/lysosomal compartments

Katia Cortese, Mark T. Howes, Richard Lundmark, Erica Tagliatti, Paola Bagnato, Annalisa Petrelli, Maria Bono, Harvey T. McMahon, Robert G. Parton, Carlo Tacchetti

Research output: Contribution to journalArticlepeer-review

Abstract

The ErbB2 receptor is a clinically validated cancer target whose internalization and trafficking mechanisms remain poorly understood. HSP90 inhibitors, such as geldanamycin (GA), have been developed to target the receptor to degradation or to modulate downstream signaling. Despite intense investigations, the entry route and postendocytic sorting of ErbB2 upon GA stimulation have remained controversial. We report that ErbB2 levels inversely impact cell clathrin-mediated endocytosis (CME) capacity. Indeed, the high levels of the receptor are responsible for its own low internalization rate. GA treatment does not directly modulate ErbB2 CME rate but it affects ErbB2 recycling fate, routing the receptor to modified multivesicular endosomes (MVBs) and lysosomal compartments, by perturbing early/recycling endosome structure and sorting capacity. This activity occurs irrespective of the cargo interaction with HSP90, as both ErbB2 and the constitutively recycled, HSP90-independent, transferrin receptor are found within modified endosomes, and within aberrant, elongated recycling tubules, leading to modified MVBs/lysosomes. We propose that GA, as part of its anticancer activity, perturbs early/recycling endosome sorting, routing recycling cargoes toward mixed endosomal compartments.

Original languageEnglish
Pages (from-to)129-144
Number of pages16
JournalMolecular Biology of the Cell
Volume24
Issue number2
DOIs
Publication statusPublished - Jan 15 2013

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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