Recruitment and activation of SHP-1 protein-tyrosine phosphatase by human platelet endothelial cell adhesion molecule-1 (PECAM-1). Identification of immunoreceptor tyrosine-based inhibitory motif-like binding motifs and substrates.
Stimulation of platelet aggregation leads to tyrosine phosphorylation of a number of receptors and signaling molecules including platelet endothelial cell adhesion molecule-1 (PECAM-1). In this report, we demonstrate that both protein-tyrosine phosphatases SHP-1 and SHP-2 physically associate with different kinetics of assembly with tyrosine-phosphorylated human PECAM-1 during integrin alphaIIbbeta3-mediated platelet aggregation. Peptido-precipitation analysis revealed that tyrosine-phosphorylated peptides encompassing residues 658-668 and 681-691 of PECAM-1 bound specifically to both protein-tyrosine phosphatases SHP-1 and SHP-2. We further show that the association of SHP-1 with PECAM-1 occurs through the direct interaction of the src homology region 2 domains of SHP-1 with two highly conserved phosphotyrosine binding motifs within PECAM-1 having the sequences NSDVQpY663TEVQV and DTETVpY686SEVRK (where pY represents phosphotyrosine). In vitro dephosphorylation experiments using phosphotyrosyl PECAM-1 peptides encompassing either Tyr-663 or Tyr-686 revealed induction of SHP-1 catalytic activity, suggesting that PECAM-1 serves as a SHP-1 substrate. Surface plasmon resonance studies reveal that recombinant SHP-2 binds PECAM-1 phosphopeptides with 5-fold higher affinity than recombinant SHP-1. These data suggest that in hematopoietic cells such as platelets, PECAM-1 cellular signaling is regulated by the selective recruitment and activation of two distinct protein-tyrosine phosphatases, SHP-1 and SHP-2, via a common immunoreceptor tyrosine-based inhibitory-like motif.
Division of Human Immunology, Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, South Australia, 5000 Australia.
C T
CT
Hua
J R
JR
Gamble
M A
MA
Vadas
D E
DE
Jackson
D001665:Binding Sites; D001792:Blood Platelets / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D010748:Phosphopeptides / Q000378:metabolism; D010766:Phosphorylation; D010974:Platelet Aggregation; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism; D011485:Protein Binding; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism*; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D018909:src Homology Domains
D047908:Intracellular Signaling Peptides and Proteins; D010748:Phosphopeptides; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011971:Receptors, Immunologic; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases