Adaptor Proteins, Signal Transducing; Phosphorylation; Molecular Sequence Data; Lymphocytes; Humans; Fas-Associated Death Domain Protein; DNA Primers; Cysteine Endopeptidases; Cross-Linking Reagents; Cell Line; Caspases; Caspase 9; Caspase 8; Carrier Proteins; Base Sequence; Apoptosis; Antigens, CD95; Animals; Tumor Cells, Cultured
Abstract :
[en] APO-1 (Fas/CD95), a member of the tumor necrosis factor receptor superfamily, induces apoptosis upon receptor oligomerization. In a search to identify intracellular signaling molecules coupling to oligomerized APO-1, several cytotoxicity-dependent APO-1-associated proteins (CAP) were immunoprecipitated from the apoptosis-sensitive human leukemic T cell line HUT78 and the lymphoblastoid B cell line SKW6.4. CAP1-3 (27-29 kDa) and CAP4 (55 kDa), instantly detectable after the crosslinking of APO-1, were associated only with aggregated (the signaling form of APO-1) and not with monomeric APO-1. CAP1 and CAP2 were identified as serine phosphorylated MORT1/FADD. The association of CAP1-4 with APO-1 was not observed with C-terminally truncated non-signaling APO-1. In addition, CAP1 and CAP2 did not associate with an APO-1 cytoplasmic tail carrying the lprcg amino acid replacement. Moreover, no APO-1-CAP association was found in the APO-1+, anti-APO-1-resistant pre-B cell line Boe. Our data suggest that in vivo CAP1-4 are the APO-1 apoptosis-transducing molecules.
Disciplines :
Biochemistry, biophysics & molecular biology
Identifiers :
UNILU:UL-ARTICLE-2008-743
Author, co-author :
Kischkel, F. C.
Hellbardt, S.
Behrmann, Iris ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit
Germer, M.
Pawlita, M.
Krammer, P. H.
Peter, M. E.
Language :
English
Title :
Cytotoxicity-dependent APO-1 (Fas/CD95)-associated proteins form a death-inducing signaling complex (DISC) with the receptor