1. CD95 death-inducing signaling complex formation and internalization occur in lipid rafts of type I and type II cells
- Author
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Cesare Peschle, Fiorenza Lotti, Lucia Ricci-Vitiani, Isabella Parolini, Ruggero De Maria, Adriana Eramo, Carlo Messina, Massimo Sargiacomo, Matilde Todaro, Giorgio Stassi, and Giovanni Sette
- Subjects
Death Domain Receptor Signaling Adaptor Proteins ,Endosome ,T-Lymphocytes ,media_common.quotation_subject ,Immunology ,Apoptosis ,Receptors, Tumor Necrosis Factor ,Cell Line ,Membrane Microdomains ,Settore MED/04 - PATOLOGIA GENERALE ,Cell Line, Tumor ,Receptors ,Humans ,Immunology and Allergy ,fas Receptor ,FADD ,Internalization ,Lipid raft ,Lipid rafts ,Death domain ,media_common ,Tumor ,biology ,Vesicle ,Fas receptor ,Endocytosis ,Cell biology ,Protein Transport ,Cholesterol ,CD95 death-inducing signaling complex ,Caspases ,CD95 ,biology.protein ,lipids (amino acids, peptides, and proteins) ,biological phenomena, cell phenomena, and immunity ,Caspase-8 ,Tumor Necrosis Factor ,Protein Binding ,Signal Transduction - Abstract
We investigated the membrane localization of CD95 in type I and type II cells, which differ in their ability to recruit and activate caspase-8. We found that CD95 was preferentially located in lipid rafts of type I cells, while it was present both in raft and non-raft plasma membrane sub-domains of type II cells. After stimulation, CD95 located in phospholipid-rich plasma membrane was recruited to lipid rafts in both types of cells. Similarly, CD95 cross-linking resulted in caspase-independent translocation of FADD/MORT1 and caspase-8 to the lipid rafts, which was prevented by a death domain-defective receptor. CD95 internalization was then rapid in type I and delayed in type II cells and showed a substantial correlation with the kinetics of Fas-associated death domain (FADD)and caspase-8 recruitment to lipid rafts. Finally, electron microscopy analysis showed that after CD95 stimulation lipid rafts aggregated in large clusters that were internalized in endosomal vesicles, where caspase-8 underwent massive processing. Taken together, our data demonstrate that CD95 death-inducing signaling complex formation and internalization in type I and type II cells occur in lipid rafts, which are a major site of caspase-8 activation.
- Published
- 2004