Identification of interaction partners of the cytosolic polyproline region of CD95 ligand (CD178).
The CD95/Fas/Apo-1 ligand (CD95L, CD178) induces apoptosis through the death receptor CD95. CD95L was also described as a co-stimulatory receptor for T-cell activation in mice in vivo. The molecular basis for the bidirectional signaling capacity and directed expression of CD95L is unknown. In the present study we identify proteins that precipitate from T-cell lysates with constructs containing fragments of the CD95L cytosolic tail. The determined peptide mass fingerprints correspond to Grb2, actin, beta-tubulin, formin binding protein 17 (FBP17) and PACSIN2. Grb2 had been identified as a putative mediator of T-cell receptor-to-CD95L signaling before. FBP17 and PACSIN2 may be associated with expression and trafficking of CD95L. When overexpressed, CD95L co-precipitates with FBP17 and PACSIN. Protein-protein interactions are mediated via Src homology 3 (SH3) domain binding to the polyproline region of CD95L and can be abolished by mutation or deletion of the respective SH3 domain.
Ghadimi
Markus Philipp
MP
Institute of Immunology, University Hospital Kiel, Michaelisstr. 5, Kiel, Germany.
Sanzenbacher
Ralf
R
Thiede
Bernd
B
Wenzel
Jennifer
J
Jing
Qian
Q
Plomann
Markus
M
Borkhardt
Arndt
A
Kabelitz
Dieter
D
Janssen
Ottmar
O
D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D053222:Fas Ligand Protein; D050556:Fatty Acid-Binding Proteins; D051380:GRB2 Adaptor Protein; D006801:Humans; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D013601:T-Lymphocytes / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D014162:Transfection; D014404:Tubulin / Q000378:metabolism; D018909:src Homology Domains / Q000502:physiology
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C505661:FASLG protein, human; C433770:FNBP1 protein, human; D053222:Fas Ligand Protein; D050556:Fatty Acid-Binding Proteins; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D008562:Membrane Glycoproteins; C120714:PACSIN2 protein, human; D011506:Proteins; D014404:Tubulin