title: Nuclear transport of paxillin depends on focal adhesion dynamics and FAT domains.
abstract: The nuclear transport of paxillin appears to be crucial for paxillin function but the mechanism of transport remains unclear. Here, we show that the nuclear transport of paxillin is regulated by focal adhesion turnover and the presence of FAT domains. Focal adhesion turnover was controlled using triangular or circular fibronectin islands. Circular islands caused higher focal adhesion turnover and increased the nuclear transport of paxillin relative to triangular islands. Mutating several residues of paxillin had no effect on its nuclear transport, suggesting that the process is controlled by multiple domains. Knocking out FAK (also known as PTK2) and vinculin caused an increase in nuclear paxillin. This could be reversed by rescue with wild-type FAK but not by FAK with a mutated FAT domain, which inhibits paxillin binding. Expressing just the FAT domain of FAK not only brought down nuclear levels of paxillin but also caused a large immobile fraction of paxillin to be present at focal adhesions, as demonstrated by fluorescence recovery after photobleaching (FRAP) studies. Taken together, focal adhesion turnover and FAT domains regulate the nuclear localization of paxillin, suggesting a possible role for transcriptional control, through paxillin, by focal adhesions.
authors.affiliation: Mechanobiology Institute, National University of Singapore, Singapore 117411.
authors.forename: Aneesh R
authors.initials: AR
authors.lastname: Sathe
authors.affiliation: Mechanobiology Institute, National University of Singapore, Singapore 117411 Department of Biological Sciences, National University of Singapore, Singapore 117543 IFOM-NUS Joint Research Laboratory.
authors.forename: G V
authors.initials: GV
authors.lastname: Shivashankar
authors.affiliation: Mechanobiology Institute, National University of Singapore, Singapore 117411 IFOM-NUS Joint Research Laboratory Department of Biological Sciences, Columbia University, New York, NY 10027, USA ms2001@columbia.edu.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Sheetz
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000235:genetics; D002448:Cell Adhesion / Q000235:genetics*; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics; D051417:Focal Adhesion Kinase 1 / Q000235:genetics*; D022001:Focal Adhesions / Q000235:genetics* / Q000378:metabolism; D055786:Gene Knockout Techniques; D006801:Humans; D051419:Paxillin / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D000072417:Protein Domains; D016596:Vinculin / Q000235:genetics / Q000378:metabolism
chemical_list: D005353:Fibronectins; D051419:Paxillin; D016596:Vinculin; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human
keywords: FAT domain; Focal adhesion; Nucleus; Paxillin