Scientific article
Open access

Phosphorylated paxillin and phosphorylated FAK constitute subregions within focal adhesions

Published inJournal of cell science, vol. 135, no. 7, jcs258764
Publication date2022-04-01
First online date2022-04-14

Integrin-mediated adhesions are convergence points for multiple signaling pathways. Their inner structure and diverse functions can be studied with super-resolution microscopy. Here, we examined the spatial organization within focal adhesions by analyzing several adhesion proteins with structured illumination microscopy (SIM). Paxillin (Pax) serves as a scaffold protein and signaling hub in focal adhesions, and focal adhesion kinase (FAK, also known as PTK2) regulates the dynamics of adhesions. We found that their phosphorylated forms, pPax and pFAK, form spot-like, spatially defined clusters within adhesions in several cell lines and confirmed these findings with additional super-resolution techniques. These clusters showed a more regular separation from each other compared with more randomly distributed signals for FAK or paxillin. Mutational analysis indicated that the active (open) FAK conformation is a prerequisite for the pattern formation of pFAK. Live-cell super-resolution imaging revealed that organization in clusters is preserved over time for FAK constructs; however, distance between clusters is dynamic for FAK, while paxillin is more stable. Combined, these data introduce spatial clusters of pPax and pFAK as substructures in adhesions and highlight the relevance of paxillin-FAK binding for establishing a regular substructure in focal adhesions.

  • FAK
  • Focal adhesions
  • Paxillin
  • Paxillin phosphorylation
  • Super-resolution microscopy
  • Focal Adhesion Kinase 1 / genetics
  • Focal Adhesion Kinase 1 / metabolism
  • Focal Adhesion Protein-Tyrosine Kinases / metabolism
  • Focal Adhesions / metabolism
  • Paxillin / genetics
  • Paxillin / metabolism
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Signal Transduction
Citation (ISO format)
BACHMANN, Michaël et al. Phosphorylated paxillin and phosphorylated FAK constitute subregions within focal adhesions. In: Journal of cell science, 2022, vol. 135, n° 7, p. jcs258764. doi: 10.1242/jcs.258764
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Article (Published version)
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ISSN of the journal0021-9533

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