Abstract
The tumor necrosis factor family member Fas ligand (FasL) induces apoptosis in Fas receptor-expressing target cells and is an important cytotoxic effector molecule used by CTL- and NK-cells. In these hematopoietic cells, newly synthesized FasL is stored in specialized secretory lysosomes and only delivered to the cell surface upon activation and target cell recognition. FasL contains an 80-amino acid-long cytoplasmic tail, which includes a proline-rich domain as a bona fide Src homology 3 domain-binding site. This proline-rich domain has been implicated in FasL sorting to secretory lysosomes, and it may also be important for reverse signaling via FasL, which has been described to influence T-cell activation. Here we report the identification of the Src homology 3 domain-containing adaptor protein PSTPIP as a FasL-interacting partner, which binds to the proline-rich domain. PSTPIP co-expression leads to an increased intracellular localization of Fas ligand, thereby regulating extracellular availability and cytotoxic activity of the molecule. In addition, we demonstrate recruitment of the tyrosine phosphatase PTP-PEST by PSTPIP into FasL.PSTPIP.PTP-PEST complexes which may contribute to FasL reverse signaling.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Adaptor Proteins, Signal Transducing / chemistry
-
Adaptor Proteins, Signal Transducing / physiology*
-
Animals
-
Apoptosis
-
Binding Sites
-
COS Cells
-
Cell Line
-
Cell Line, Tumor
-
Cell Separation
-
Chlorocebus aethiops
-
Coculture Techniques
-
Cytoplasm / metabolism
-
Cytoskeletal Proteins / chemistry
-
Cytoskeletal Proteins / physiology*
-
DNA, Complementary / metabolism
-
Fas Ligand Protein
-
Flow Cytometry
-
Glutathione Transferase / metabolism
-
Green Fluorescent Proteins / metabolism
-
HeLa Cells
-
Humans
-
Immunoprecipitation
-
Lysosomes / chemistry
-
Lysosomes / metabolism
-
Membrane Glycoproteins / metabolism*
-
Mice
-
Mice, Inbred C57BL
-
Microscopy, Confocal
-
Models, Biological
-
Plasmids / metabolism
-
Proline / chemistry
-
Protein Binding
-
Protein Biosynthesis
-
Protein Structure, Tertiary
-
Protein Tyrosine Phosphatase, Non-Receptor Type 12
-
Protein Tyrosine Phosphatases / chemistry
-
Rats
-
Signal Transduction
-
Spleen / cytology
-
T-Lymphocytes / cytology
-
T-Lymphocytes / metabolism
-
Transfection
-
Tumor Necrosis Factors / metabolism*
-
Two-Hybrid System Techniques
-
Tyrosine / chemistry
-
src Homology Domains
Substances
-
Adaptor Proteins, Signal Transducing
-
Cytoskeletal Proteins
-
DNA, Complementary
-
FASLG protein, human
-
Fas Ligand Protein
-
Fasl protein, mouse
-
Faslg protein, rat
-
Membrane Glycoproteins
-
PSTPIP1 protein, human
-
Tumor Necrosis Factors
-
Green Fluorescent Proteins
-
Tyrosine
-
Proline
-
Glutathione Transferase
-
PTPN12 protein, human
-
Protein Tyrosine Phosphatase, Non-Receptor Type 12
-
Protein Tyrosine Phosphatases
-
Ptpn12 protein, mouse
-
Ptpn12 protein, rat