Cutting edge: the B cell surface protein CD72 recruits the tyrosine phosphatase SHP-1 upon tyrosine phosphorylation

T Adachi, H Flaswinkel, H Yakura, M Reth… - The Journal of …, 1998 - journals.aai.org
T Adachi, H Flaswinkel, H Yakura, M Reth, T Tsubata
The Journal of Immunology, 1998journals.aai.org
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 …
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.
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