title: Structural and mechanistic insights into the interaction between Pyk2 and paxillin LD motifs.
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 (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 (paxillin(133-290)) binds to Pyk2-FAT as a 1:1 complex. However, our data suggest that the Pyk2-FAT and paxillin complex is dynamic and it appears to be a mixture of two distinct conformations of paxillin that almost equally compete for Pyk2-FAT binding. These studies provide insight into the underlying selectivity of paxillin for Pyk2 and FAK that may influence the differing behavior of these two closely related kinases in focal adhesion sites.
authors.affiliation: Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Murugendra S
authors.initials: MS
authors.lastname: Vanarotti
authors.affiliation: Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Darcie J
authors.initials: DJ
authors.lastname: Miller
authors.affiliation: Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Cristina D
authors.initials: CD
authors.lastname: Guibao
authors.affiliation: Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Nourse
authors.affiliation: Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. Electronic address: Jie.Zheng@stjude.org.
authors.forename: Jie J
authors.initials: JJ
authors.lastname: Zheng
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002151:Calorimetry; D002645:Chickens; D018360:Crystallography, X-Ray; D051418:Focal Adhesion Kinase 2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D051419:Paxillin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013816:Thermodynamics
chemical_list: D030161:Avian Proteins; D051419:Paxillin; D051418:Focal Adhesion Kinase 2
keywords: cell adhesion and signaling; dynamic complex; focal adhesion kinase; paxillin binding; proline-rich tyrosine kinase 2