PKCθ-mediated serine/threonine phosphorylations of FAK govern adhesion and protrusion dynamics within the lamellipodia of migrating breast cancer cells

Cancer Lett. 2022 Feb 1;526:112-130. doi: 10.1016/j.canlet.2021.11.026. Epub 2021 Nov 23.

Abstract

The cytoskeleton and cell-matrix adhesions constitute a dynamic network that controls cellular behavior during development and cancer. The Focal Adhesion Kinase (FAK) is a central actor of these cell dynamics, promoting cell-matrix adhesion turnover and active membrane fluctuations. However, the initial steps leading to FAK activation and subsequent promotion of cell dynamics remain elusive. Here, we report that the serine/threonine kinase PKCθ participates in the initial steps of FAK activation. PKCθ, which is strongly expressed in aggressive human breast cancers, controls the dynamics of cell-matrix adhesions and active protrusions through direct FAK activation, thereby promoting cell invasion and lung metastases. Using various tools for in vitro and live cell studies, we precisely decipher the molecular mechanisms of FAK activation. PKCθ directly interacts with the FAK FERM domain to open FAK conformation through PKCθ's specific V3 domain, while phosphorylating FAK at newly identified serine/threonine residues within nascent adhesions, inducing cell dynamics and aggressive behavior. This study thus places PKCθ-directed FAK opening and phosphorylations as an original mechanism controlling dynamic, migratory, and invasive abilities of aggressive breast cancer cells, further strengthening the emerging oncogenic function of PKCθ.

Keywords: Cancer cell migration and invasion; Cell dynamics; FAK; PKCθ; Phosphorylation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Breast Neoplasms / physiopathology*
  • Cell Adhesion / physiology
  • Cell Line, Tumor
  • Cell Movement / physiology
  • Cytoskeleton / metabolism*
  • Female
  • Focal Adhesion Kinase 1 / metabolism*
  • Heterografts
  • Humans
  • MCF-7 Cells
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Phosphorylation
  • Protein Kinase C-theta / metabolism*
  • Protein Serine-Threonine Kinases / metabolism*
  • Pseudopodia / metabolism*

Substances

  • Focal Adhesion Kinase 1
  • PTK2 protein, human
  • Protein Serine-Threonine Kinases
  • Protein Kinase C-theta