Endo- and exocytic rate constants for spontaneous and protein kinase C-activated T cell receptor cycling

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To determine the rate constants of spontaneous and activated TCR cycling, we examined TCR endo- and exocytosis in the human T cell line Jurkat by three different methods. Using a simple kinetic model for TCR cycling and non-linear regression analyses, we found that the spontaneous endocytic rate constant of the TCR was low (approximately 0.012 min(-1)) whereas the spontaneous exocytic rate constant was similar to that of other cycling receptors (approximately 0.055 min(-1)). Following protein kinase C activation (PKC) the endocytic rate constant was increased tenfold (to approximately 0.128 min(-1)) whereas the exocytic rate constant was unaffected. Thus, the TCR becomes a rapidly cycling receptor with kinetics similar to classical cycling receptors subsequent to PKC activation. This results in a reduction of the half-life of cell surface expressed TCR from approximately 58 to 6 min and allows rapid redistribution of the TCR during T cell activation.
Original languageEnglish
JournalEuropean Journal of Immunology
Issue number3
Pages (from-to)616-26
Number of pages10
Publication statusPublished - 2002

Bibliographical note

Keywords: Amino Acid Motifs; Antibodies, Monoclonal; Antigens, CD3; Down-Regulation; Endocytosis; Enzyme Activation; Exocytosis; Fluorescein-5-isothiocyanate; Fluorescent Dyes; Humans; Jurkat Cells; Kinetics; Phosphorylation; Protein Kinase C; Protein Processing, Post-Translational; Receptors, Antigen, T-Cell; Up-Regulation

ID: 8544638