Characterization of phosphotyrosine binding motifs in the cytoplasmic domain of B and T lymphocyte attenuator required for association with protein tyrosine phosphatases SHP-1 and SHP-2.
B and T lymphocytes express receptors providing positive and negative co-stimulatory signals. We recently identified a novel co-stimulatory molecule, B and T lymphocyte attenuator (BTLA), which exerts inhibitory effects on B and T lymphocytes. The cytoplasmic domain of murine and human BTLA share three conserved tyrosine-based signaling motifs, a Grb-2 recognition consensus, and two immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Phosphorylation of the cytoplasmic domain of BTLA induced the association with the protein tyrosine phosphatases SHP-1 and SHP-2. Association of SHP-1 and SHP-2 to other receptors can involve recruitment to either a single receptor ITIM or to two receptor ITIMs. Here, we analyzed the requirements of BTLA interaction with SHP-1 and SHP-2 in a series of murine and human BTLA mutants. For human BTLA, mutations of either Y257 or Y282, but not Y226, abrogated association with both SHP-1 and SHP-2. For murine BTLA, mutation of either Y274 or Y299, but not Y245, also abrogated association with both SHP-1 and SHP-2. These results indicate that for both murine and human BTLA, association with SHP-1 or SHP-2 requires both of conserved ITIM motifs and does not involve the conserved Grb-2 consensus. Thus, similar to the bisphosphoryl tyrosine-based activation motif (BTAM) by which the Grb-2 associated binder (Gab1), PDGF receptor, and PECAM-1 recruit SHP-2, BTLA also relies on dual ITIMs for its association with the phosphatases SHP-1 and SHP-2.
Gavrieli
Maya
M
Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
Watanabe
Norihiko
N
Loftin
Susan K
SK
Murphy
Theresa L
TL
Murphy
Kenneth M
KM
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D019000:Phosphotyrosine; D011485:Protein Binding; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000145:classification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017385:Sequence Homology; D013045:Species Specificity; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000737:chemistry* / Q000378:metabolism*
C482586:BTLA protein, human; D047908:Intracellular Signaling Peptides and Proteins; D011971:Receptors, Immunologic; D011994:Recombinant Proteins; D019000:Phosphotyrosine; 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; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse