title: The B cell surface protein CD72 recruits the tyrosine phosphatase SHP-1 upon tyrosine phosphorylation.
abstract: Activation signals of lymphocytes are negatively regulated by the membrane molecules carrying the immunoreceptor tyrosine-based inhibition motif (ITIM). Upon tyrosine phosphorylation, ITIMs recruit SH2-containing phosphatases such as SHP-1, resulting in down-modulation of cell activation. We showed that the cytoplasmic domain of the CD72 molecule carries an ITIM and is associated in vitro with SHP-1 upon tyrosine phosphorylation. Moreover, cross-linking of B cell Ag receptor (BCR) enhances both tyrosine phosphorylation of CD72 and association of CD72 with SHP-1 in B cell line WEHI-231. These results indicate that CD72 recruits SHP-1 upon tyrosine phosphorylation induced by BCR signaling, suggesting that CD72 is a negative regulator of BCR signaling.
authors.affiliation: Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Adachi
authors.forename: H
authors.initials: H
authors.lastname: Flaswinkel
authors.forename: H
authors.initials: H
authors.lastname: Yakura
authors.forename: M
authors.initials: M
authors.lastname: Reth
authors.forename: T
authors.initials: T
authors.lastname: Tsubata
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000502:physiology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000502:physiology*; D011947:Receptors, Antigen, B-Cell / Q000502:physiology; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; C064228:CD72 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D011947:Receptors, Antigen, B-Cell; D014443:Tyrosine; 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