Paxillin Is Tyrosine-phosphorylated by and Preferentially Associates with the Calcium-dependent Tyrosine Kinase in Rat Liver Epithelial Cells

Abstract

We and others have recently cloned a non-receptor, calcium-dependent tyrosine kinase (CADTK; also known as PYK2, CAKβ, and RAFTK) that shares both overall domain structure and 45% amino acid identity with p125FAK. We have studied the signaling, activation, and potential function of these related enzymes in GN4 rat liver epithelial cells that express CADTK and p125FAK at roughly similar levels. p125FAK is nearly fully tyrosine-phosphorylated in resting GN4 cells. In contrast, while CADTK is not tyrosine-autophosphorylated in untreated cells, angiotensin II increases CADTK Tyr(P) by 5–10-fold. With regard to signaling, CADTK activation is correlated with stimulation of c-Jun N-terminal kinase and p70S6Kpathways but not with the stimulation of mitogen-activated protein kinase or p90RSK. In this report we assessed the contribution of CADTK and p125FAK to tyrosine phosphorylation of focal contact proteins. In adherent GN4 cells, the constitutive activity of p125FAK was correlated with basal paxillin, tensin, and p130CAS tyrosine phosphorylation. A rapid increase in the tyrosine phosphorylation of each protein was detected after treatment with angiotensin II or other agonists that stimulate CADTK; the prolonged 3–4-fold increase in paxillin tyrosine phosphorylation was the most substantial change. In the WB cell line that expresses 3-fold less CADTK than GN4 cell line agonist-dependent paxillin tyrosine phosphorylation is similarly reduced. Immunoprecipitation of CADTK from GN4 cells revealed CADTK·paxillin complexes that persisted in 500 mm NaCl but not in 0.1% SDS cell lysis buffer. The complexes were largely independent of the tyrosine phosphorylation state of either protein. Surprisingly, we did not detect p125FAK·paxillin complexes in immunoprecipitates using either of two p125FAKantibodies. When CADTK and p125FAK were transiently overexpressed in 293(T) cells, both enzymes associated with paxillin, but the avidity of CADTK appeared to be greater. In addition, in transfected 293(T) cells, complexes between CADTK and another potential substrate, p130CAS, were detected. In summary, in GN4 rat liver epithelial cells stimulation of CADTK was highly correlated with paxillin tyrosine phosphorylation; in addition, CADTK but not p125FAK was complexed to paxillin at detectable levels. This suggests that agonist-dependent cytoskeletal changes in epithelial cells might proceed, in part, by CADTK-dependent mechanisms. We and others have recently cloned a non-receptor, calcium-dependent tyrosine kinase (CADTK; also known as PYK2, CAKβ, and RAFTK) that shares both overall domain structure and 45% amino acid identity with p125FAK. We have studied the signaling, activation, and potential function of these related enzymes in GN4 rat liver epithelial cells that express CADTK and p125FAK at roughly similar levels. p125FAK is nearly fully tyrosine-phosphorylated in resting GN4 cells. In contrast, while CADTK is not tyrosine-autophosphorylated in untreated cells, angiotensin II increases CADTK Tyr(P) by 5–10-fold. With regard to signaling, CADTK activation is correlated with stimulation of c-Jun N-terminal kinase and p70S6Kpathways but not with the stimulation of mitogen-activated protein kinase or p90RSK. In this report we assessed the contribution of CADTK and p125FAK to tyrosine phosphorylation of focal contact proteins. In adherent GN4 cells, the constitutive activity of p125FAK was correlated with basal paxillin, tensin, and p130CAS tyrosine phosphorylation. A rapid increase in the tyrosine phosphorylation of each protein was detected after treatment with angiotensin II or other agonists that stimulate CADTK; the prolonged 3–4-fold increase in paxillin tyrosine phosphorylation was the most substantial change. In the WB cell line that expresses 3-fold less CADTK than GN4 cell line agonist-dependent paxillin tyrosine phosphorylation is similarly reduced. Immunoprecipitation of CADTK from GN4 cells revealed CADTK·paxillin complexes that persisted in 500 mm NaCl but not in 0.1% SDS cell lysis buffer. The complexes were largely independent of the tyrosine phosphorylation state of either protein. Surprisingly, we did not detect p125FAK·paxillin complexes in immunoprecipitates using either of two p125FAKantibodies. When CADTK and p125FAK were transiently overexpressed in 293(T) cells, both enzymes associated with paxillin, but the avidity of CADTK appeared to be greater. In addition, in transfected 293(T) cells, complexes between CADTK and another potential substrate, p130CAS, were detected. In summary, in GN4 rat liver epithelial cells stimulation of CADTK was highly correlated with paxillin tyrosine phosphorylation; in addition, CADTK but not p125FAK was complexed to paxillin at detectable levels. This suggests that agonist-dependent cytoskeletal changes in epithelial cells might proceed, in part, by CADTK-dependent mechanisms. The once separate fields of cell structure and signal transduction have converged due to a number of recent observations. Growth factors and hormones are now known to regulate cell shape and mobility; conversely, proteins involved in cell attachment and cytoskeleton formation can clearly be induced to generate intracellular signals (1Hall A. Annu. Rev. Cell Biol. 1994; 10: 31-54Crossref PubMed Scopus (768) Google Scholar, 2Clark A.E. Brugge J.S. Science. 1995; 268: 233-239Crossref PubMed Scopus (2816) Google Scholar, 3Richardson A. Parsons J.T. BioEssays. 1995; 17: 229-236Crossref PubMed Scopus (256) Google Scholar, 4Schaller M.D. Parsons J.T. Curr. Opin. Cell Biol. 1994; 6: 705-710Crossref PubMed Scopus (495) Google Scholar, 5Jockusch B.M. Bubeck P. Giehl K. Kroemker M. Moschner J. Rothkegel M. Rudiger M. Schluter K. Stanke G. Winkler J. Annu. Rev. Cell Dev. Biol. 1995; 11: 379-416Crossref PubMed Scopus (430) Google Scholar, 6Schwartz M.A. Schaller M.D. Ginsberg M.H. Annu. Rev. Cell Dev. Biol. 1995; 11: 549-599Crossref PubMed Scopus (1469) Google Scholar). For example, integrins engagement stimulates tyrosine phosphorylation (7Kornberg L. Earp H.S. Parsons J.T. Schaller M. Juliano R.L. J. Biol. Chem. 1992; 267: 23439-23442Abstract Full Text PDF PubMed Google Scholar, 8Kornberg L. Earp H.S. Turner C. Prokop C. Juliano R.L. Proc. Natl. Acad. Sci. U. S. A. 1991; 88: 8392-8396Crossref PubMed Scopus (632) Google Scholar, 9Guan J.L. Trevithick J.E. Hynes R.O. Cell Regul. 1991; 2: 951-964Crossref PubMed Scopus (473) Google Scholar, 10Guan J.L. Shalloway D. Nature. 1992; 358: 690-692Crossref PubMed Scopus (724) Google Scholar) and alters gene expression (6Schwartz M.A. Schaller M.D. Ginsberg M.H. Annu. Rev. Cell Dev. Biol. 1995; 11: 549-599Crossref PubMed Scopus (1469) Google Scholar, 11Juliano R.L. Haskill S. J. Cell Biol. 1993; 120: 577-585Crossref PubMed Scopus (1540) Google Scholar). Several years ago our laboratory noted that EGF 1The abbreviations used are: EGFepidermal growth factorCADTKcalcium-dependent tyrosine kinasep125FAKp125 focal adhesion tyrosine kinasep130CASp130 Crk-associated substratep70S6Kp70 ribosomal S6 kinasep90RSKp90 ribosomal S6 kinaseMAPKmitogen-activated protein acid treatment of rat liver epithelial cells of protein tyrosine the after the of Tyr(P) Earp H.S. J. Biol. Chem. Full Text PDF PubMed Google Scholar). of the in the in to Tyr(P) The activity in part, due to stimulation of a protein tyrosine kinase that appeared to be by the signal Prokop Earp H.S. Biol. 10: PubMed Scopus Google Scholar). activation was with the intracellular by angiotensin II or Prokop Earp H.S. Biol. 10: PubMed Scopus Google Scholar, Earp H.S. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar). increases intracellular protein kinase also tyrosine by of cells with intracellular Prokop Earp H.S. Biol. 10: PubMed Scopus Google Scholar, Earp H.S. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar). growth calcium-dependent tyrosine kinase focal adhesion tyrosine kinase Crk-associated ribosomal S6 kinase ribosomal S6 kinase mitogen-activated protein kinase tyrosine phosphorylation angiotensin II acid We have now the calcium-dependent tyrosine kinase from rat liver epithelial cells H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar) and a D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). CADTK the protein as S. P. J. Nature. 1995; PubMed Scopus Google S. S. D. J. S. J.E. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google and rat K. M. K. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). CADTK and p125FAK are highly and is The 45% overall amino acid identity is the tyrosine kinase and as a is to focal M.D. Parsons J.T. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar) a of proteins the to the cytoskeleton M.D. Parsons J.T. Curr. Opin. Cell Biol. 1994; 6: 705-710Crossref PubMed Scopus (495) Google Scholar) and is in to with the (7Kornberg L. Earp H.S. Parsons J.T. Schaller M. Juliano R.L. J. Biol. Chem. 1992; 267: 23439-23442Abstract Full Text PDF PubMed Google Scholar, 10Guan J.L. Shalloway D. Nature. 1992; 358: 690-692Crossref PubMed Scopus (724) Google Scholar, Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar, L. Schaller M.D. Parsons J.T. Brugge J.S. J. Cell Biol. 1992; PubMed Scopus (632) Google Scholar). This is correlated with but or not be related to signals that the K. Juliano R.L. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, S. J.S. J. Cell Biol. 1995; PubMed Scopus Google Scholar, K. K. K. K. K. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar, P. Nature. 1994; PubMed Scopus Google Scholar, Biol. 1995; 6: Scopus Google Scholar). In summary, p125FAK at a and is of cell structure and p125FAK not or but can with proteins and When p125FAK other proteins tyrosine kinase Biol. 1995; PubMed Google Scholar, Schaller M.D. Parsons J.T. Biol. 1994; Scholar, M.D. Parsons J.T. Biol. 1995; PubMed Scopus Google Scholar). p125FAK also a that can with proteins p130CAS Parsons J.T. Biol. PubMed Scopus Google Scholar, Proc. Natl. Acad. Sci. U. S. A. 1995; PubMed Scopus Google Scholar, C. C. M. G. M. J. Cell Biol. 1995; PubMed Scopus Google Scholar, Parsons J.T. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). the the focal adhesion domain that or complexes with focal adhesion proteins paxillin Schaller M.D. Parsons J.T. J. Cell Biol. 1993; PubMed Scopus Google Scholar). The with paxillin two the focal adhesion in paxillin to p125FAK to focal K. C. J. 1995; PubMed Scopus Google Scholar). others have that paxillin not be p125FAK focal Schaller M.D. Parsons J.T. Biol. 1995; 6: PubMed Scopus Google Scholar). tyrosine-phosphorylated p125FAK tyrosine these enzymes and other proteins focal in a potential B.M. Bubeck P. Giehl K. Kroemker M. Moschner J. Rothkegel M. Rudiger M. Schluter K. Stanke G. Winkler J. Annu. Rev. Cell Dev. Biol. 1995; 11: 379-416Crossref PubMed Scopus (430) Google Scholar, 6Schwartz M.A. Schaller M.D. Ginsberg M.H. Annu. Rev. Cell Dev. Biol. 1995; 11: 549-599Crossref PubMed Scopus (1469) Google Scholar, S. J.S. J. Cell Biol. 1995; PubMed Scopus Google Scholar). p125FAK most studied in a cell that not express CADTK K. M. K. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar) not The kinase is in and is in epithelial cells and cells D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, S. P. J. Nature. 1995; PubMed Scopus Google Scholar, S. S. D. J. S. J.E. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). CADTK is not from cells of as we have to be by agonists in rat cells. S. and L. M. cells express or the other at cell rat liver epithelial cells express CADTK and p125FAK. CADTK is by a signal using either the or protein kinase of H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar, D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, S. P. J. Nature. 1995; PubMed Scopus Google Scholar). the of protein kinase to be not the and protein kinase activation is In cells, p125FAK is by and other J. Turner J. Biol. Chem. 1993; 268: Full Text PDF PubMed Google Scholar, J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. 1993; 268: Full Text PDF PubMed Google Scholar). in cells in both enzymes are the stimulation of CADTK activity is of and is and growth stimulation than changes in p125FAK D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, S. P. J. Nature. 1995; PubMed Scopus Google For example, in adherent WB and GN4 cells, p125FAK a basal of tyrosine phosphorylation and is by II CADTK is by D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). In p125FAK activation is correlated with stimulation of the a is not The calcium-dependent activation of CADTK in GN4 liver epithelial cells not D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) but is correlated with substantial increases in c-Jun N-terminal kinase and the kinase D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, Earp H.S. Biol. 1995; PubMed Scopus Google J. D. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). of with and phosphorylation of cytoskeletal a of In this we report that II treatment stimulates the tyrosine phosphorylation of paxillin, tensin, and The paxillin phosphorylation is the most and p125FAK basal paxillin tyrosine phosphorylation in adherent GN4 cells CADTK activity is the rapid and paxillin tyrosine phosphorylation after stimulation with both the activation and expression of the of tyrosine-phosphorylated p125FAK and CADTK are similar in GN4 cells, paxillin a with complexes not be detected. of CADTK and p125FAK by revealed the of paxillin CADTK and also in GN4 cells, activation of CADTK increases paxillin tyrosine changes that are a of protein tyrosine phosphorylation in part, by p125FAK. II was from and in mm acid to and were from and and in and were from was from and were by Parsons of and Schaller of was from and were from and was by of CADTK were to two proteins and of rat as D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). liver epithelial cells or were in with and as H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). cells with 293(T) were by and in with Cell lysis was as H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). cells with agonists were cell lysis buffer. of lysis was used and to as lysis mm mm mm mm and mm mm mm mm and or lysis mm mm mm 0.1% and cell lysis the were and of Cell were by at at and the protein to In a 500 of cell was by with the at by of of protein A or protein complexes were by the was used a complexes were with the lysis and in buffer. were to to and detected by the with the as H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). were with either or and using to the When were in the mm at and with another The CADTK was as D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) and was a p125FAK the was by of The and were transfected 293(T) cells with to the transfected cells were and with and the were by by with paxillin, or II and increase the tyrosine phosphorylation of proteins with a of and Prokop Earp H.S. Biol. 10: PubMed Scopus Google Scholar, Earp H.S. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar, H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). of the tyrosine-phosphorylated proteins was as the calcium-dependent tyrosine kinase engagement stimulates p125FAK and paxillin Tyr(P) and II to increase paxillin tyrosine phosphorylation in cells J. Cell Sci. 1995; PubMed Google Scholar, S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google we of the GN4 cell tyrosine was Immunoprecipitation and revealed that II treatment of GN4 cells paxillin tyrosine phosphorylation by that persisted at tyrosine phosphorylation be detected at with the tyrosine phosphorylation of CADTK not II stimulation also paxillin phosphorylation or The while detected at at II treatment also and p130CAS tyrosine phosphorylation. In to paxillin, both and p130CAS of tyrosine phosphorylation by and Tyr(P) This the of CADTK tyrosine phosphorylation but also that and p130CAS are to tyrosine than but not p130CAS also a with II treatment The Tyr(P) as assessed by is that the of both paxillin and as due to or by tyrosine phosphorylation at by this liver epithelial cells express both p125FAK and with II to a in p125FAK tyrosine phosphorylation and activity from detectable to increases H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). This is due to the that p125FAK is in GN4 cells. In contrast, CADTK tyrosine phosphorylation is detectable in cells but is induced by II or other CADTK or p125FAK stimulation correlated with changes in paxillin tyrosine GN4 cells were with a of agonists known to stimulate CADTK by of the Tyr(P) of paxillin, and p125FAK. that CADTK tyrosine phosphorylation were the most at paxillin tyrosine phosphorylation In the of CADTK and paxillin Tyr(P) was For example, prolonged EGF treatment CADTK tyrosine phosphorylation and paxillin tyrosine phosphorylation II and CADTK and paxillin Tyr(P) In contrast, p125FAK tyrosine phosphorylation was by treatment basal paxillin tyrosine phosphorylation be by constitutive p125FAK The between CADTK and paxillin tyrosine phosphorylation suggests that and other agonists stimulate paxillin tyrosine phosphorylation the of the two paxillin tyrosine phosphorylation was in cells known to express similar of p125FAK but of We that GN4 cells by of a rat liver epithelial cell have tyrosine phosphorylation than WB cell Prokop Earp H.S. Biol. 10: PubMed Scopus Google Scholar). Immunoprecipitation with CADTK that GN4 cells CADTK tyrosine phosphorylation than similarly WB cells D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). II treatment in paxillin tyrosine phosphorylation in GN4 cells than in WB cells p125FAK expression and tyrosine in to II stimulation was similar in the GN4 and WB cell the similar basal of paxillin tyrosine phosphorylation in WB and GN4 cells correlated with the p125FAK The paxillin tyrosine phosphorylation in GN4 cells was the that CADTK activation paxillin Tyr(P) CADTK activation by II or in part, a calcium-dependent the of II and paxillin tyrosine GN4 cells were with the that the signal in these cells Prokop Earp H.S. Biol. 10: PubMed Scopus Google Scholar, Earp H.S. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar). the increase in both CADTK and paxillin tyrosine phosphorylation in to II A and The of was not II also CADTK activity protein kinase C. CADTK activation paxillin tyrosine phosphorylation with both basal p125FAK and paxillin tyrosine phosphorylation that calcium-dependent activation of CADTK is in paxillin tyrosine phosphorylation in to II and a of the of cytoskeletal is at focal the of the cell to the K. J. Cell Biol. PubMed Scopus Google Scholar, BioEssays. 1994; PubMed Scopus Google Scholar). that and cytoskeletal p125FAK tyrosine and paxillin tyrosine phosphorylation in cells L. Schaller M.D. Parsons J.T. Brugge J.S. J. Cell Biol. 1992; PubMed Scopus (632) Google Scholar, J. Biol. Chem. 1994; Full Text PDF PubMed Google J. J. Biol. Chem. 1993; 268: Full Text PDF PubMed Google Scholar, S. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). or paxillin tyrosine GN4 cells were with and with II or another that stimulates CADTK activity D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google cell not and II and CADTK A and basal p125FAK tyrosine phosphorylation The of paxillin tyrosine phosphorylation was both basal and paxillin Tyr(P) were nearly by our is that p125FAK is basal paxillin tyrosine phosphorylation in adherent cells and CADTK is the induced this suggests that both The in that II stimulates paxillin tyrosine phosphorylation and that this agonist-dependent is correlated with activation and expression of CADTK than p125FAK. paxillin with p125FAK in Schaller M.D. Parsons J.T. Biol. 1995; 6: PubMed Scopus Google we tyrosine-phosphorylated paxillin to CADTK or p125FAK in and GN4 cells. GN4 cells were with or II and with to CADTK or with of two to or CADTK tyrosine phosphorylation was in cells, and the was tyrosine-phosphorylated in both and GN4 cells of cell were used and were with the the in suggests that of tyrosine-phosphorylated p125FAK is at and in is than that of we not have that both we have Tyr(P) in the The and in both are highly we have the tyrosine of CADTK and that this CADTK in the that p125FAK and S. the of tyrosine phosphorylation in GN4 cell CADTK and p125FAK a that p125FAK and CADTK expression are similar in these cells. Surprisingly, Tyr(P) proteins were associated with but was or Tyr(P) protein associated with p125FAK of the CADTK with paxillin that at of the Tyr(P) protein was paxillin The suggests that while paxillin can with K. C. J. 1995; PubMed Scopus Google and Schaller M.D. Parsons J.T. Biol. 1995; 6: PubMed Scopus Google and in adherent cells, or tyrosine-phosphorylated paxillin can be in p125FAK·paxillin CADTK with tyrosine-phosphorylated paxillin in GN4 cells, we the of the CADTK·paxillin GN4 cells were with or and in lysis and 0.1% SDS buffer. Cell were using the was with and a paxillin nearly of paxillin in CADTK in from either or cells. II or treatment did not the to treatment The were the after lysis in a a that domain was in 0.1% SDS that of or both proteins was The that in is of the proteins and not CADTK or paxillin tyrosine phosphorylation. We the cytoskeleton structure with the or p125FAK in CADTK associated with paxillin of the GN4 cells were with or CADTK tyrosine phosphorylation and paxillin tyrosine phosphorylation in cells did not the complexes were not detected these or The used to p125FAK is the that the in Schaller M.D. Parsons J.T. Biol. 1995; 6: PubMed Scopus Google Scholar). after with p125FAK also to detect complexes in GN4 cells not the paxillin p125FAK and CADTK were overexpressed by by in 293(T) cells. 293(T) cells p125FAK expression but we not detect in after phosphorylation was than that of CADTK Immunoprecipitation p125FAK·paxillin this as the our to detect p125FAK·paxillin in GN4 cells. another potential CADTK we CADTK immunoprecipitates from 293(T) cells the of CADTK in 293(T) cells of as by In to paxillin, the was not detected in GN4 cells not but the in a of this potential kinase II signal and at tyrosine kinase that we have recently and cloned and to as CADTK D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). CADTK is by a the is as the of GN4 cells with also but the activation is than that of II or and is also the by and other signals regulate CADTK is In GN4 cells, a signal and also stimulates both c-Jun N-terminal kinase and but not or D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, Earp H.S. Biol. 1995; PubMed Scopus Google Scholar, J. D. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). in cells, agonist-dependent stimulation tyrosine phosphorylation and We are to the of this cell in CADTK and in addition, CADTK and the the between CADTK and we the tyrosine phosphorylation of paxillin, a protein tyrosine engagement of cell integrins Schaller M.D. Parsons J.T. Biol. 1995; 6: PubMed Scopus Google Scholar). In cells not express paxillin and p125FAK and tyrosine-phosphorylated in to a of growth and J. Turner J. Biol. Chem. 1993; 268: Full Text PDF PubMed Google Scholar, J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar, S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar, J. J. Biol. Chem. 1993; 268: Full Text PDF PubMed Google Scholar, S. J. Biol. Chem. 1994; Full Text PDF PubMed Google Scholar). can also be in by and both of are p125FAK M.D. Parsons J.T. Biol. 1995; PubMed Scopus Google Scholar). In this we that II tyrosine phosphorylation of paxillin, tensin, and p130CAS in adherent GN4 rat liver epithelial cells. The paxillin is the The in paxillin tyrosine phosphorylation by CADTK agonists is rapid with CADTK activation a of agonists with the CADTK expression and activation in GN4 and WB cells and is largely calcium-dependent A of this is in p125FAK is at that are similar or than the of tyrosine-phosphorylated is known that the in p125FAK is M.D. Parsons J.T. Biol. 1995; PubMed Scopus Google Scholar, M.D. Parsons J.T. Biol. 1994; PubMed Scopus Google Scholar) and we have the is the in the of tyrosine phosphorylation of these two enzymes a of p125FAK is tyrosine-phosphorylated in untreated cells. p125FAK activity is to be by the of the basal of paxillin tyrosine phosphorylation. This is with the that basal of paxillin Tyr(P) is in WB and GN4 cell similar of p125FAK II treatment p125FAK tyrosine phosphorylation and activity H.S. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google but II increases CADTK tyrosine phosphorylation and activity D. M. Earp H.S. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). This activation with a substantial increase in paxillin and but increases in and p130CAS tyrosine phosphorylation. The intracellular CADTK and paxillin tyrosine phosphorylation. In cells, less p125FAK tyrosine phosphorylation than CADTK that CADTK is the tyrosine kinase the increase in paxillin tyrosine phosphorylation. we other CADTK tyrosine that of p125FAK domain to tyrosine as tyrosine A.E. Brugge J.S. Science. 1995; 268: 233-239Crossref PubMed Scopus (2816) Google Scholar, Biol. 1995; PubMed Google Scholar, Schaller M.D. Parsons J.T. Biol. 1994; Scholar, M.D. Parsons J.T. Biol. 1994; PubMed Scopus Google Biol. 1995; PubMed Scopus Google Scholar). enzymes in We have a CADTK is to in p125FAK M.D. Parsons J.T. Biol. 1994; PubMed Scopus Google Scholar, Biol. 1995; PubMed Scopus Google and both are to the by the domain of and M. G. S. J.E. 1993; Full Text PDF PubMed Scopus Google Scholar). that CADTK complexes can the N-terminal of paxillin in M. D. and S. but this not the of a tyrosine a of p125FAK Tyr(P) in resting cells, at The increases in both CADTK and paxillin tyrosine phosphorylation CADTK phosphorylation of paxillin but not CADTK by of another tyrosine In this CADTK and a tyrosine kinase with CADTK than other of activation might that CADTK The CADTK and p125FAK is the focal adhesion domain that two K. C. J. 1995; PubMed Scopus Google Scholar). two are paxillin have paxillin and and and are in and with and with that CADTK·paxillin complexes not either tyrosine phosphorylation or cytoskeleton and that CADTK with paxillin protein the two and In we have that a of paxillin to CADTK by in of the rat CADTK using Surprisingly, was not detected in GN4 cells protein expression of p125FAK and CADTK to be be to the or and involved in CADTK and p125FAK with cytoskeletal proteins. This be used to in epithelial cells, the of CADTK paxillin is than that of p125FAK. are in the cells, p125FAK and CADTK are not to be cell For example, CADTK fully p125FAK as by gene in D. S. K. S. J. M. S. Nature. 1995; PubMed Scopus Google Scholar). the two enzymes have example, cell to to activation J. S. S. 88: PubMed Google Scholar). The that CADTK and p125FAK to have to with paxillin suggests in with to the the between these two protein tyrosine II treatment also increases p130CAS and tyrosine and of CADTK in 293(T) cells complexes cells with or of cells both p130CAS and tyrosine phosphorylation S. J.S. J. Cell Biol. 1995; PubMed Scopus Google Scholar, Parsons J.T. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, A. Parsons J.T. K. J. Cell Sci. 1995; PubMed Google Scholar, S. K. J. Biol. Chem. 1993; 268: Full Text PDF PubMed Google Scholar, K. J. Biol. Chem. Full Text Full Text PDF Scopus Google Scholar). both can these two cytoskeletal proteins in BioEssays. 1994; PubMed Scopus Google Scholar, K. S. Biol. PubMed Google Scholar). p130CAS can with p125FAK in domain Proc. Natl. Acad. Sci. U. S. A. 1995; PubMed Scopus Google Scholar, Parsons J.T. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). the of with the p130CAS is to in and this be the of detected in transfected 293(T) cells CADTK p130CAS and to be The of tyrosine phosphorylation of paxillin, p130CAS, and in is activity paxillin and complexes with other cytoskeletal proteins as and BioEssays. 1994; PubMed Scopus Google Scholar, BioEssays. 1994; PubMed Scopus Google Scholar). paxillin, p130CAS, and also the proteins as M.D. Parsons J.T. Biol. 1995; PubMed Scopus Google Scholar, Parsons J.T. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, J.E. C. Biol. 1993; PubMed Scopus Google Scholar, A. S. J. 1994; PubMed Scopus Google Scholar). In can with a number of proteins as two and and a tyrosine S. S. S. M. K. K. M. Proc. Natl. Acad. Sci. U. S. A. 1994; PubMed Scopus Google Scholar, M. K. S. S. S. Biol. 1994; PubMed Scopus Google Scholar, D. Sci. 1994; Full Text PDF PubMed Scopus Google Scholar). be to CADTK paxillin, p130CAS, and tyrosine phosphorylation at than by CADTK in proteins and We and We and the We also and Schaller and We