Degranulation plays an essential part in regulating cell surface expression of Fas ligand in T cells and natural killer cells.
Nat Med
; 5(1): 90-6, 1999 Jan.
Article
em En
| MEDLINE
| ID: mdl-9883845
ABSTRACT
Fas ligand (FasL) triggers apoptosis during cytotoxicity mediated by cytotoxic T lymphocytes and during immune downregulation. The ability of T cells and natural killer cells to trigger apoptosis through this mechanism is controlled by the cell surface expression of FasL (ref. 2). Because FasL expression is up-regulated on activation, FasL was thought to be delivered directly to the cell surface. Here we show that newly synthesized FasL is stored in specialized secretory lysosomes in both CD4+ and CD8+ T cells and natural killer cells, and that polarized degranulation controls the delivery of FasL to the cell surface. In this way, FasL-mediated apoptosis is finely controlled by receptor-mediated target-cell recognition. The cytoplasmic tail of FasL contains signals that sort FasL to secretory lysosomes in hemopoietic cells. This pathway may provide a general mechanism for controlling the cell surface appearance of proteins involved in immune regulation.
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Base de dados:
MEDLINE
Assunto principal:
Glicoproteínas de Membrana
/
Células Matadoras Naturais
/
Linfócitos T CD4-Positivos
/
Degranulação Celular
/
Linfócitos T CD8-Positivos
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
1999
Tipo de documento:
Article