CD3 gamma contains a phosphoserine-dependent di-leucine motif involved in down-regulation of the T cell receptor
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CD3 gamma contains a phosphoserine-dependent di-leucine motif involved in down-regulation of the T cell receptor. / Dietrich, J; Hou, X; Wegener, A M; Geisler, C.
In: EMBO Journal, Vol. 13, No. 9, 1994, p. 2156-66.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - CD3 gamma contains a phosphoserine-dependent di-leucine motif involved in down-regulation of the T cell receptor
AU - Dietrich, J
AU - Hou, X
AU - Wegener, A M
AU - Geisler, C
N1 - Keywords: Amino Acid Sequence; Antigens, CD3; Cell Line; Coated Pits, Cell-Membrane; Down-Regulation; Endocytosis; Enzyme Activation; Humans; Leucine; Molecular Sequence Data; Phosphorylation; Phosphoserine; Point Mutation; Protein Kinase C; Receptors, Antigen, T-Cell; T-Lymphocytes; Transfection; Tyrosine
PY - 1994
Y1 - 1994
N2 - Several cell surface receptors including the T cell receptor (TCR) are phosphorylated and down-regulated following activation of protein kinase C (PKC). Among other substrates the activated PKC in T cells phosphorylates the CD3 gamma subunit of the TCR. To investigate the role of CD3 gamma phosphorylation in PKC-mediated TCR down-regulation, point mutated CD3 gamma cDNA was transfected into the CD3 gamma-negative T cell line JGN and CD3 gamma transfectants were analysed. Phosphorylation at S126 but not S123 in the cytoplasmic tail of CD3 gamma was required for PKC-mediated down-regulation of the TCR. Furthermore, analysis of a series of CD3 gamma truncation mutants indicated that in addition to S126 phosphorylation a motif C-terminal of S126 was required for TCR down-regulation. Point mutation analyses confirmed this observation and demonstrated that a membrane-proximal di-leucine motif (L131 and L132) in the cytoplasmic tail of CD3 gamma was required for PKC-mediated TCR down-regulation in addition to phosphorylation at S126. Incubation of T cells in hypertonic medium known to disrupt normal clathrin lattices severely inhibited PKC-mediated TCR down-regulation in non-mutated T cells, indicating that the TCR was down-regulated by endocytosis via clathrin coated pits. Based on the present results and previously published observations on intracellular receptor sorting, a general model for intracellular sorting of receptors containing di-leucine- or tyrosine-based motifs is proposed.
AB - Several cell surface receptors including the T cell receptor (TCR) are phosphorylated and down-regulated following activation of protein kinase C (PKC). Among other substrates the activated PKC in T cells phosphorylates the CD3 gamma subunit of the TCR. To investigate the role of CD3 gamma phosphorylation in PKC-mediated TCR down-regulation, point mutated CD3 gamma cDNA was transfected into the CD3 gamma-negative T cell line JGN and CD3 gamma transfectants were analysed. Phosphorylation at S126 but not S123 in the cytoplasmic tail of CD3 gamma was required for PKC-mediated down-regulation of the TCR. Furthermore, analysis of a series of CD3 gamma truncation mutants indicated that in addition to S126 phosphorylation a motif C-terminal of S126 was required for TCR down-regulation. Point mutation analyses confirmed this observation and demonstrated that a membrane-proximal di-leucine motif (L131 and L132) in the cytoplasmic tail of CD3 gamma was required for PKC-mediated TCR down-regulation in addition to phosphorylation at S126. Incubation of T cells in hypertonic medium known to disrupt normal clathrin lattices severely inhibited PKC-mediated TCR down-regulation in non-mutated T cells, indicating that the TCR was down-regulated by endocytosis via clathrin coated pits. Based on the present results and previously published observations on intracellular receptor sorting, a general model for intracellular sorting of receptors containing di-leucine- or tyrosine-based motifs is proposed.
M3 - Journal article
C2 - 8187769
VL - 13
SP - 2156
EP - 2166
JO - E M B O Journal
JF - E M B O Journal
SN - 0261-4189
IS - 9
ER -
ID: 8545944