4prz
From Proteopedia
Caspase-8 specific unnatural amino acid peptides
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 PubMedCaspases are fundamental to many essential biological processes, including apoptosis, differentiation, and inflammation. Unregulated caspase activity is also implicated in the development and progression of several diseases, such as cancer, neurodegenerative disorders, and sepsis. Unfortunately, it is difficult to determine exactly which caspase(s) of the 11 isoforms that humans express is responsible for specific biological functions. This lack of resolution is primarily due to highly homologous active sites and overlapping substrates. Currently available peptide-based inhibitors and probes are based on specificity garnered from peptide substrate libraries. For example, the canonical tetrapeptide LETD was discovered as the canonical sequence that is optimally recognized by caspase-8; however, LETD-based inhibitors and substrates promiscuously bind to other isoforms with equal affinity, including caspases-3, -6, and -9. In order to mitigate this problem, we report the identification of a new series of compounds that are >100-fold selective for inhibiting the initiator caspases-8 and -9 over the executioner caspases-3, -6, and -7. Selective inhibition of initiator versus executioner caspases using small peptides containing unnatural amino acids.,Vickers CJ, Gonzalez-Paez GE, Litwin KM, Umotoy JC, Coutsias EA, Wolan DW ACS Chem Biol. 2014 Oct 17;9(10):2194-8. doi: 10.1021/cb5004256. Epub 2014 Aug 5. PMID:25079698[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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