FARP1, ARHGEF39, and TIAM2 are essential receptor tyrosine kinase effectors for Rac1-dependent cell motility in human lung adenocarcinoma

Cell Rep. 2021 Nov 2;37(5):109905. doi: 10.1016/j.celrep.2021.109905.


Despite the undisputable role of the small GTPase Rac1 in the regulation of actin cytoskeleton reorganization, the Rac guanine-nucleotide exchange factors (Rac-GEFs) involved in Rac1-mediated motility and invasion in human lung adenocarcinoma cells remain largely unknown. Here, we identify FARP1, ARHGEF39, and TIAM2 as essential Rac-GEFs responsible for Rac1-mediated lung cancer cell migration upon EGFR and c-Met activation. Noteworthily, these Rac-GEFs operate in a non-redundant manner by controlling distinctive aspects of ruffle dynamics formation. Mechanistic analysis reveals a leading role of the AXL-Gab1-PI3K axis in conferring pro-motility traits downstream of EGFR. Along with the positive association between the overexpression of Rac-GEFs and poor lung adenocarcinoma patient survival, we show that FARP1 and ARHGEF39 are upregulated in EpCam+ cells sorted from primary human lung adenocarcinomas. Overall, our study reveals fundamental insights into the complex intricacies underlying Rac-GEF-mediated cancer cell motility signaling, hence underscoring promising targets for metastatic lung cancer therapy.

Keywords: ARHGEF39; AXL; EGFR; FARP1; Rac-GEF; Rac1; TIAM2; lung cancer; migration; ruffles.

Publication types

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

MeSH terms

  • A549 Cells
  • Adenocarcinoma of Lung / enzymology*
  • Adenocarcinoma of Lung / genetics
  • Adenocarcinoma of Lung / pathology
  • Aged
  • Axl Receptor Tyrosine Kinase
  • Cell Movement
  • Epithelial Cell Adhesion Molecule / metabolism
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism
  • Female
  • Gene Expression Regulation, Neoplastic
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / metabolism*
  • Humans
  • Lung Neoplasms / enzymology*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / pathology
  • Male
  • Middle Aged
  • Neoplasm Invasiveness
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-met / genetics
  • Proto-Oncogene Proteins c-met / metabolism
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / metabolism*
  • Rho Guanine Nucleotide Exchange Factors / genetics
  • Rho Guanine Nucleotide Exchange Factors / metabolism*
  • Signal Transduction
  • rac1 GTP-Binding Protein / genetics
  • rac1 GTP-Binding Protein / metabolism*


  • ARHGEF39 protein, human
  • EPCAM protein, human
  • Epithelial Cell Adhesion Molecule
  • FARP1 protein, human
  • Guanine Nucleotide Exchange Factors
  • Proto-Oncogene Proteins
  • RAC1 protein, human
  • Rho Guanine Nucleotide Exchange Factors
  • TIAM2 protein, human
  • EGFR protein, human
  • ErbB Receptors
  • MET protein, human
  • Proto-Oncogene Proteins c-met
  • Receptor Protein-Tyrosine Kinases
  • rac1 GTP-Binding Protein
  • Axl Receptor Tyrosine Kinase
  • AXL protein, human