FAF1 phosphorylation by AKT accumulates TGF-β type II receptor and drives breast cancer metastasis

Nat Commun. 2017 Apr 26:8:15021. doi: 10.1038/ncomms15021.

Abstract

TGF-β is pro-metastatic for the late-stage breast cancer cells. Despite recent progress, the regulation of TGF-β type II receptor remains uncertain. Here we report that FAF1 destabilizes TβRII on the cell surface by recruiting the VCP/E3 ligase complex, thereby limiting excessive TGF-β response. Importantly, activated AKT directly phosphorylates FAF1 at Ser 582, which disrupts the FAF1-VCP complex and reduces FAF1 at the plasma membrane. The latter results in an increase in TβRII at the cell surface that promotes both TGF-β-induced SMAD and non-SMAD signalling. We uncover a metastasis suppressing role for FAF1 through analyses of FAF1-knockout animals, various in vitro and in vivo models of epithelial-to-mesenchymal transition and metastasis, an MMTV-PyMT transgenic mouse model of mammary tumour progression and clinical breast cancer samples. These findings describe a previously uncharacterized mechanism by which TβRII is tightly controlled. Together, we reveal how SMAD and AKT pathways interact to confer pro-oncogenic responses to TGF-β.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Apoptosis Regulatory Proteins
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Cell Movement
  • Female
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • MCF-7 Cells
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Nude
  • Neoplasm Metastasis
  • Phosphorylation
  • Protein Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Receptor, Transforming Growth Factor-beta Type II
  • Receptors, Transforming Growth Factor beta / metabolism*
  • Transplantation, Heterologous

Substances

  • Adaptor Proteins, Signal Transducing
  • Apoptosis Regulatory Proteins
  • FAF1 protein, human
  • Receptors, Transforming Growth Factor beta
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Receptor, Transforming Growth Factor-beta Type II