A kinase inhibitor screen reveals protein kinase C-dependent endocytic recycling of ErbB2 in breast cancer cells

Tameka A. Bailey, Haitao Luan, Eric Tom, Timothy Alan Bielecki, Bhopal Mohapatra, Gulzar Ahmad, Manju George, David Lee Kelly, Amarnath Natarajan, Srikumar M. Raja, Vimla Band, Hamid Band

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19 Scopus citations

Abstract

ErbB2 overexpression drives oncogenesis in 20-30% cases of breast cancer. Oncogenic potential of ErbB2 is linked to inefficient endocytic traffic into lysosomes and preferential recycling. However, regulation of ErbB2 recycling is incompletely understood. We used a high-content immunofluorescence imagingbased kinase inhibitor screen on SKBR-3 breast cancer cells to identify kinases whose inhibition alters the clearance of cell surface ErbB2 induced by Hsp90 inhibitor 17-AAG. Less ErbB2 clearance was observed with broad-spectrum PKC inhibitor Ro 31-8220. A similar effect was observed with Go 6976, a selective inhibitor of classical Ca2+-dependent PKCs (α, β1, βII, and γ). PKC activation by PMA promoted surface ErbB2 clearance but without degradation, and ErbB2 was observed to move into a juxtanuclear compartment where it colocalized with PKC-α and PKC-δ together with the endocytic recycling regulator Arf6. PKC-α knockdown impaired the juxtanuclear localization of ErbB2. ErbB2 transit to the recycling compartment was also impairedupon PKC-δknockdown. PMA-induced Erkphosphorylation was reduced by ErbB2 inhibitor lapatinib, as well as by knockdown of PKC-δ but not that of PKC-α. Our results suggest that activation of PKC-α and -δ mediates a novel positive feedback loop by promoting ErbB2 entry into the endocytic recycling compartment, consistent with reported positive roles for these PKCs in ErbB2-mediated tumorigenesis. As the endocytic recycling compartment/pericentrion has emerged as a PKC-dependent signaling hub for G-protein-coupled receptors, our findings raise the possibility that oncogenesis by ErbB2 involves previously unexplored PKC-dependent endosomal signaling.

Original languageEnglish (US)
Pages (from-to)30443-30458
Number of pages16
JournalJournal of Biological Chemistry
Volume289
Issue number44
DOIs
Publication statusPublished - Oct 31 2014

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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