Cloning and Characterization of Lnk, a Signal Transduction Protein that Links T-Cell Receptor Activation Signal to Phospholipase Cγ_1, Grb2, and Phosphatidylinositol 3-Kinase
Abstract
A cDNA encoding a signal transduction protein with a Src homology 2 (SH2) domain and a tyrosine phosphorylation site was cloned from a rat lymph node cDNA library. This protein, which we designate Lnk, has a calculated molecular weight of 33,988. When T lymphocytes were activated by antibody-mediated crosslinking of the T-cell receptor and CD4, Lnk became tyrosine phosphorylated. In activated T lymphocytes, phospholipase C gamma 1, phosphatidylinositol 3-kinase, and Grb-2 coimmunoprecipitated with Lnk. Our results suggest that Lnk becomes tyrosine phosphorylated and links the immediate tyrosine phosphorylation signals of the TCR to the distal phosphatidylinositol 3-kinase, phospholipase C gamma 1 and Ras signaling pathways through its multifunctional tyrosine phosphorylation site.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- December 1995
- DOI:
- Bibcode:
- 1995PNAS...9211618H