title: Comparison of p56lck and p59fyn protein expression in thymocyte subsets, peripheral T cells, NK cells, and lymphoid cell lines.
abstract: The expression of the src-family kinases, p56lck and p59fyn, is critical for thymocyte development and TCR-mediated signal transduction, and may be important for signaling through other lymphoid receptors as well. Overexpression studies have demonstrated that the levels of p56lck and p59fyn expression can affect T cell development and signaling through the TCR. Therefore, it is likely that their exact expression levels play an important role in modulating signaling in thymocytes, mature T cells, and other lymphocytes. Here, we used quantitative immunoblotting to measure p56lck and p59fyn protein expression levels in thymocyte subsets, peripheral T cells, NK cells, and lymphoid cell lines. p59fyn expression levels were similar to p56lck in most cells that were examined demonstrating that p59fyn is abundantly expressed in T cells. In addition, we found that p56lck protein expression is equivalent in CD4 and CD8 double-negative, double-positive, and single-positive thymocytes. In contrast, p59fyn expression levels were significantly lower in double-positive thymocytes than in the other thymocyte subpopulations. Finally, we demonstrate that p56lck and p59fyn expression varies greatly in a number of cell lines used to study T cell activation and that IL-2 treatment can dynamically regulate p56lck and p59fyn expression in some cells.
authors.affiliation: Center for Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Olszowy
authors.forename: P L
authors.initials: PL
authors.lastname: Leuchtmann
authors.forename: A
authors.initials: A
authors.lastname: Veillette
authors.forename: A S
authors.initials: AS
authors.lastname: Shaw
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000378:metabolism*; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000276:immunology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000276:immunology; D051076:Proto-Oncogene Proteins c-fyn; D016176:T-Lymphocyte Subsets / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases / Q000096:biosynthesis* / Q000276:immunology
chemical_list: D007376:Interleukin-2; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C494957:FYN protein, human; C494960:Fyn protein, mouse; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases