5h31
Structural basis for dimerization of the death effector domains of Caspase-8Structural basis for dimerization of the death effector domains of Caspase-8
Structural highlights
Disease[CASP8_HUMAN] Defects in CASP8 are the cause of caspase-8 deficiency (CASP8D) [MIM:607271]. CASP8D is a disorder resembling autoimmune lymphoproliferative syndrome (ALPS). It is characterized by lymphadenopathy, splenomegaly, and defective CD95-induced apoptosis of peripheral blood lymphocytes (PBLs). It leads to defects in activation of T-lymphocytes, B-lymphocytes, and natural killer cells leading to immunodeficiency characterized by recurrent sinopulmonary and herpes simplex virus infections and poor responses to immunization.[1] Function[CASP8_HUMAN] Most upstream protease of the activation cascade of caspases responsible for the TNFRSF6/FAS mediated and TNFRSF1A induced cell death. Binding to the adapter molecule FADD recruits it to either receptor. The resulting aggregate called death-inducing signaling complex (DISC) performs CASP8 proteolytic activation. The active dimeric enzyme is then liberated from the DISC and free to activate downstream apoptotic proteases. Proteolytic fragments of the N-terminal propeptide (termed CAP3, CAP5 and CAP6) are likely retained in the DISC. Cleaves and activates CASP3, CASP4, CASP6, CASP7, CASP9 and CASP10. May participate in the GZMB apoptotic pathways. Cleaves ADPRT. Hydrolyzes the small-molecule substrate, Ac-Asp-Glu-Val-Asp-|-AMC. Likely target for the cowpox virus CRMA death inhibitory protein. Isoform 5, isoform 6, isoform 7 and isoform 8 lack the catalytic site and may interfere with the pro-apoptotic activity of the complex.[2] [3] Publication Abstract from PubMedCaspase-8 is a key mediator in various biological processes such as apoptosis, necroptosis, inflammation, T/B cells activation, and cell motility. Caspase-8 is characterized by the N-terminal tandem death effector domains (DEDs) and the C-terminal catalytic protease domain. The DEDs mediate diverse functions of caspase-8 through homotypic interactions of the DEDs between caspase-8 and its partner proteins. Here, we report the first crystal structure of the DEDs of caspase-8. The overall structure of the DEDs of caspase-8 is similar to that of the DEDs of vFLIP MC159, which is composed of two tandem death effector domains that closely associate with each other in a head-to-tail manner. Structural analysis reveals distinct differences in the region connecting helices alpha2b and alpha4b in the second DED of the DEDs between caspase-8 and MC159, in which the helix alpha3b in MC159 is replaced by a loop in caspase-8. Moreover, the different amino acids in this region might confer the distinct features of solubility and aggregation for the DEDs of caspase-8 and MC159. Crystal structure of the death effector domains of caspase-8.,Shen C, Yue H, Pei J, Guo X, Wang T, Quan JM Biochem Biophys Res Commun. 2015 Jul 31;463(3):297-302. doi:, 10.1016/j.bbrc.2015.05.054. Epub 2015 May 20. PMID:26003730[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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