title: Phosphorylation of mouse thymocyte CD4 and CD8: regulation of surface expression.
abstract: Murine T cell surface antigens, CD4 and CD8 are phosphorylated in response to phorbol 12-myristate 13-acetate, a protein kinase C activator, but not phosphorylated after concanavalin A, Ca2+ ionophore or dibutyryl-cAMP treatment. We examined the cell surface expression of both antigens and show that surface CD4 on CD4+CD8+ and CD4+CD8- thymocytes is rapidly decreased after PMA treatment, while CD8 expression is unaffected. Prolonged PMA treatment, which down-regulates protein kinase C, allows CD4 reexpression only in the CD4+CD8- population, suggesting that different mechanisms of cell surface antigen expression are operating in the two thymocyte subpopulations.
authors.affiliation: Department of Genetics, Stanford University, School of Medicine, California 94305.
authors.forename: M
authors.initials: M
authors.lastname: Tagawa
authors.forename: T
authors.initials: T
authors.lastname: Koike
authors.forename: L C
authors.initials: LC
authors.lastname: Griffith
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism*; D015704:CD4 Antigens / Q000378:metabolism*; D016827:CD8 Antigens / Q000378:metabolism*; D002478:Cells, Cultured; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D051379:Mice; D008807:Mice, Inbred BALB C; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism*
chemical_list: D000954:Antigens, Surface; D015704:CD4 Antigens; D016827:CD8 Antigens; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate