title: Cellular settings mediating Src Substrate switching between focal adhesion kinase tyrosine 861 and CUB-domain-containing protein 1 (CDCP1) tyrosine 734.
abstract: Reciprocal interactions between Src family kinases (SFKs) and focal adhesion kinase (FAK) are critical during changes in cell attachment. Recently it has been recognized that another SFK substrate, CUB-domain-containing protein 1 (CDCP1), is differentially phosphorylated during these events. However, the molecular processes underlying SFK-mediated phosphorylation of CDCP1 are poorly understood. Here we identify a novel mechanism in which FAK tyrosine 861 and CDCP1-Tyr-734 compete as SFK substrates and demonstrate cellular settings in which SFKs switch between these sites. Our results show that stable CDCP1 expression induces robust SFK-mediated phosphorylation of CDCP1-Tyr-734 with concomitant loss of p-FAK-Tyr-861 in adherent HeLa cells. SFK substrate switching in these cells is dependent on the level of expression of CDCP1 and is also dependent on CDCP1-Tyr-734 but is independent of CDCP1-Tyr-743 and -Tyr-762. In HeLa CDCP1 cells, engagement of SFKs with CDCP1 is accompanied by an increase in phosphorylation of Src-Tyr-416 and a change in cell morphology to a fibroblastic appearance dependent on CDCP1-Tyr-734. SFK switching between FAK-Tyr-861 and CDCP1-Tyr-734 also occurs during changes in adhesion of colorectal cancer cell lines endogenously expressing these two proteins. Consistently, increased p-FAK-Tyr-861 levels and a more epithelial morphology are seen in colon cancer SW480 cells silenced for CDCP1. Unlike protein kinase Cδ, FAK does not appear to form a trimeric complex with Src and CDCP1. These data demonstrate novel aspects of the dynamics of SFK-mediated cell signaling that may be relevant during cancer progression.
authors: Mater Medical Research Institute, Aubigny Place, Raymond Terrace, South Brisbane, Queensland 4101; Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059.
authors: Andreas
authors: A
authors: Wortmann
authors: Mater Medical Research Institute, Aubigny Place, Raymond Terrace, South Brisbane, Queensland 4101.
authors: Yaowu
authors: Y
authors: He
authors: Mater Medical Research Institute, Aubigny Place, Raymond Terrace, South Brisbane, Queensland 4101.
authors: Melinda E
authors: ME
authors: Christensen
authors: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059.
authors: MayLa
authors: M
authors: Linn
authors: Wesley Medical Centre, Auchenflower, Queensland 4066, Australia.
authors: John W
authors: JW
authors: Lumley
authors: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059.
authors: Pamela M
authors: PM
authors: Pollock
authors: Mater Medical Research Institute, Aubigny Place, Raymond Terrace, South Brisbane, Queensland 4101.
authors: Nigel J
authors: NJ
authors: Waterhouse
authors: Mater Medical Research Institute, Aubigny Place, Raymond Terrace, South Brisbane, Queensland 4101. Electronic address: jhooper@mmri.mater.org.au.
authors: John D
authors: JD
authors: Hooper
mesh_terms: D015703:Antigens, CD / Q000737:chemistry*; D000951:Antigens, Neoplasm; D001665:Binding Sites; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D018450:Disease Progression; D005347:Fibroblasts / Q000378:metabolism; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000737:chemistry*; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods; D009363:Neoplasm Proteins / Q000737:chemistry*; D010766:Phosphorylation; D014443:Tyrosine / Q000737:chemistry*; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D000951:Antigens, Neoplasm; C432044:CDCP1 protein, human; D015815:Cell Adhesion Molecules; D009363:Neoplasm Proteins; D014443:Tyrosine; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases