Intact LIM 3 and LIM 4 domains of paxillin are required for the association to a novel polyproline region (Pro 2) of protein-tyrosine phosphatase-PEST.
The focal adhesion protein p130(Cas) was identified as a substrate for the protein-tyrosine phosphatase (PTP)-PEST, and the specificity of this interaction is mediated by a dual mechanism involving a Src homology 3 domain-mediated binding and PTP domain recognition. Recently, paxillin was also demonstrated to interact with PTP-PEST (Shen, Y., Schneider, G., Cloutier, J. F., Veillette, A., and Schaller, M. D. (1998) J. Biol. Chem. 273, 6474-6481). In the present study, we show that amino acids 344-397 of PTP-PEST are sufficient for the binding to paxillin. We demonstrate that a proline-rich segment of PTP-PEST (Pro 2), 355PPEPHPVPPILTPSPPSAFP374, is essential for this interaction in vivo. Furthermore, mutation of proline residues within the Pro 2 motif reveal that proline 362 is critical for the binding of paxillin. Conversely, using deletion and point mutants of paxillin, LIM 3 and 4 domains were both found to be necessary for binding of PTP-PEST. Finally, using a "substrate trapping" approach, we demonstrate that, unlike p130(Cas), paxillin is not a substrate for PTP-PEST. In conclusion, we show that a novel proline-rich motif found in PTP-PEST serves as a ligand for the LIM domains of paxillin. Interestingly, the focal adhesion targeting of paxillin is mediated by LIM 3. Thus, we propose that PTP-PEST, by a competition with the ligand of paxillin in the focal adhesion complex, could contribute to the removal of paxillin from the adhesion sites and consequently promote focal adhesion turnover.
Department of Biochemistry, McGill University, Montréal, Québec H3G 1Y6, Canada.
J F
JF
Côté
C E
CE
Turner
M L
ML
Tremblay
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D051380:GRB2 Adaptor Protein; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D051419:Paxillin; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D054594:Protein Tyrosine Phosphatase, Non-Receptor Type 12; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D050717:Retinoblastoma-Like Protein p130; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C493841:BCAR1 protein, human; C493842:Bcar1 protein, mouse; D050719:Crk-Associated Substrate Protein; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495949:Grb2 protein, mouse; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; C496062:Pxn protein, mouse; D050717:Retinoblastoma-Like Protein p130; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; C516738:PTPN12 protein, human; D054594:Protein Tyrosine Phosphatase, Non-Receptor Type 12; D017027:Protein Tyrosine Phosphatases; C516739:Ptpn12 protein, mouse