PMID: 25174335

Authors:

Vanarotti MS, Miller DJ, Guibao CD, Nourse A, Zheng JJ

Title:

Structural and mechanistic insights into the interaction between Pyk2 and Paxillin LD motifs.

Journal:

J Mol Biol. 2014 Aug 28. pii: S0022-2836(14)00457-4. doi:, 10.1016/j.jmb.2014.08.014.

Abstract:

Proline-rich tyrosine kinase 2 (Pyk2) is a member of the focal adhesion kinase (FAK) subfamily of cytoplasmic tyrosine kinases. The C-terminal Pyk2 focal adhesion-targeting (Pyk2-FAT) domain binds to paxillin, an adhesion molecule. Paxillin has five leucine-aspartate (LD) motifs (LD1-LD5). Here, we show that the second LD motif of paxillin, LD2, interacts with Pyk2-FAT, similar to the known Pyk2-FAT/LD4 interaction. Both LD motifs can target two ligand-binding sites on Pyk2-FAT. Interestingly, they also share similar binding affinity for Pyk2-FAT with preferential association to one site relative to the other. Nevertheless, the LD2-LD4 region of paxillin (paxillin133-290) binds to Pyk2-FAT as a 1:1 complex. However, our data suggests that the Pyk2-FAT and paxillin complex is dynamic and it appears to be a mixture of two distinct conformations of paxillin which almost equally compete for Pyk2-FAT binding. These studies provide insight into the underlying selectivity of paxillin for Pyk2 and FAK which may influence the differing behavior of these two closely-related kinases in focal adhesion sites.