Conformational dynamics and multi-modal interaction of Paxillin with the Focal Adhesion Targeting Domain

Published

June 18, 2025

Author(s)

Supriyo Bhattacharya, Yanan He, Yihong Chen, Atish Mohanty, Alexander Grishaev, Prakash Kulkarni, Ravi Salgia, John Orban

Abstract

Paxillin (PXN) is a key component of the focal adhesion (FA) complex that plays an essential role in cell attachment, migration/metastasis, and drug resistance. The N-domain of PXN is mostly intrinsically disordered and contains five short leucine/aspartate-rich (LD) motifs of ≈12 residues each that are predicted to be helical. PXN interacts with Focal Adhesion Kinase (FAK), another central part of the FA complex. This interaction involves the 4-helix bundle targeting domain of FAK (FAT) and the LD motifs of PXN. Previous studies of PXN binding to FAT were mostly on short peptides corresponding to the LD2 and LD4 motifs, but it is not understood how the entire disordered region of human PXN interacts with FAT. Here, using a combination of NMR, SAXS, and MD simulations, we demonstrate that the PXN N-domain is conformationally restricted and binds to FAT in multiple ways through its LD1, LD2, and LD4 motifs while still remaining largely disordered. The main anchoring interaction is through LD2, with both LD1-2/FAT and LD2-4/FAT complexes present in equilibrium. In addition, the LD1, LD2, and LD4 motifs each bind to both the alpha2/alpha3 and alpha1/alpha4 sites on FAT. The results indicate a highly dynamic and multi-modal interaction between PXN and FAT, providing a framework for understanding how post-translational modifications and other protein ligands may alter the equilibrium between these differently bound states in the fuzzy complex formed by PXN/FAT.

Citation

Science Advances

Volume

11

Pub Type

Journals

Download Paper

https://doi.org/10.1126/sciadv.adt9936

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Keywords

Intrinsically disordered protein, fuzzy complex, Paxillin, focal adhesion, NMR, SAXS, molecular dynamics

Citation

Bhattacharya, S. , He, Y. , Chen, Y. , Mohanty, A. , Grishaev, A. , Kulkarni, P. , Salgia, R. and Orban, J. (2025), Conformational dynamics and multi-modal interaction of Paxillin with the Focal Adhesion Targeting Domain, Science Advances, [online], https://doi.org/10.1126/sciadv.adt9936, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=958902 (Accessed October 23, 2025)