Regulation of mouse PECAM-1 tyrosine phosphorylation by the Src and Csk families of protein-tyrosine kinases.
PECAM-1 is an adhesion molecule expressed on hemopoietic and endothelial cells. Recently, it was observed that PECAM-1 becomes tyrosine-phosphorylated in response to a variety of physiological stimuli. Furthermore, tyrosine-phosphorylated PECAM-1 was shown to associate with SHP-2, a Src homology 2 (SH2) domain-containing protein-tyrosine phosphatase expressed ubiquitously. In light of the significance of tyrosine protein phosphorylation as a regulatory mechanism, we wished to understand better the nature and impact of the protein-tyrosine kinases (PTKs) mediating PECAM-1 tyrosine phosphorylation. Through reconstitution experiments in COS-1 cells, we determined that mouse PECAM-1 could be tyrosine-phosphorylated by Src-related PTKs and Csk-related PTKs, but not by other kinases such as Syk, Itk, and Pyk2. Using site-directed mutagenesis and peptide phosphorylation studies, we found that these PTKs were efficient at phosphorylating Tyr-686, but not Tyr-663, of PECAM-1. Src-related enzymes also phosphorylated mouse PECAM-1 at one or more yet to be identified sites. In other studies, we demonstrated that phosphorylation of PECAM-1 by Src or Csk family kinases was sufficient to trigger its association with SHP-2. Moreover, it was able to promote binding of PECAM-1 to SHP-1, a SHP-2-related protein-tyrosine phosphatase expressed in hemopoietic cells. Taken together, these findings indicated that the Src and Csk families of kinases are strong candidates for mediating tyrosine phosphorylation of PECAM-1 and triggering its association with SH2 domain-containing phosphatases under physiological circumstances.
Cao
M Y
MY
McGill Cancer Centre, McGill University, Montréal, Québec H3G 1Y6, Canada.
Huber
M
M
Beauchemin
N
N
Famiglietti
J
J
Albelda
S M
SM
Veillette
A
A
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism*; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D014443:Tyrosine / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism*
D047908:Intracellular Signaling Peptides and Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D014443:Tyrosine; C086603:Matk protein, mouse; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D019061:src-Family Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases