Direct transmembrane clustering and cytoplasmic dimerization of focal adhesion kinase initiates its tyrosine phosphorylation

Ben Zion Katz*, Shingo Miyamoto, Hidemi Teramoto, Muriel Zohar, Dmitry Krylov, Charles Vinson, J. Silvio Gutkind, Kenneth M. Yamada

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We investigated mechanisms for inducing focal adhesion kinase (FAK) tyrosine phosphorylation and their ability to trigger MAP kinase signaling using transmembrane chimeras that localize FAK and its mutants to the plasma membrane. We tested whether tyrosine phosphorylation was triggered by FAK transmembrane aggregation using antibodies against the chimeric extracellular domain. Experimental clustering of chimeras containing integrin β cytoplasmic domains or FAK induced FAK tyrosine phosphorylation and trans-phosphorylation of endogenous FAK, as well as strong ERK activation. Next, we examined whether lower-order molecular proximity, namely dimerization, could regulate FAK tyrosine phosphorylation. We found that even relatively low-affinity FAK dimerization (Kd=3.9×10-5 M), in either of two different orientations, could induce FAK tyrosine phosphorylation. However, this cytoplasmic FAK dimerization could not induce MAP kinase activation or trans-phosphorylation of endogenous FAK. We conclude that dimerization of FAK is sufficient to induce its tyrosine phosphorylation, but that higher-order molecular proximity (clustering) at the cell membrane is apparently needed for additional biochemical events. This study identifies a proximity mechanism for regulating the initiation of FAK-mediated biochemical signaling.

Original languageEnglish
Pages (from-to)141-152
Number of pages12
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1592
Issue number2
DOIs
StatePublished - 21 Oct 2002
Externally publishedYes

Keywords

  • Clustering
  • Dimerization
  • FAK
  • MAP kinase
  • Tyrosine phosphorylation

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