Unliganded EphA3 dimerization promoted by the SAM domain

Deo R. Singh, Qing Qing Cao, Christopher King, Matt Salotto, Fozia Ahmed, Xiang Yang Zhou, Elena B. Pasquale, Kalina Hristova

Research output: Contribution to journalArticle


The erythropoietin-producing hepatocellular carcinoma A3 (EphA3) receptor tyrosine kinase (RTK) regulates morphogenesis during development and is overexpressed and mutated in a variety of cancers. EphA3 activation is believed to follow a 'seeding mechanism' model, in which ligand binding to the monomeric receptor acts as a trigger for signal-productive receptor clustering. We study EphA3 lateral interactions on the surface of live cells and we demonstrate that EphA3 forms dimers in the absence of ligand binding. We further show that these dimers are stabilized by interactions involving the EphA3 sterile α-motif (SAM) domain. The discovery of unliganded EphA3 dimers challenges the current understanding of the chain of EphA3 activation events and suggests that EphA3 may follow the 'pre-formed dimer' model of activation known to be relevant for other receptor tyrosine kinases. The present work also establishes a new role for the SAM domain in promoting Eph receptor lateral interactions and signalling on the cell surface.

Original languageEnglish (US)
Pages (from-to)101-109
Number of pages9
JournalBiochemical Journal
Issue number1
StatePublished - Oct 1 2015



  • Dimerization
  • EphA3
  • SAM domain
  • Signaling

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Singh, D. R., Cao, Q. Q., King, C., Salotto, M., Ahmed, F., Zhou, X. Y., Pasquale, E. B., & Hristova, K. (2015). Unliganded EphA3 dimerization promoted by the SAM domain. Biochemical Journal, 471(1), 101-109. https://doi.org/10.1042/BJ20150433