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“Smac”ing the Life out of XIAP
Author(s) -
Greig James,
Akteke Elfin,
Doshi Sarah,
He Eva,
Fujikawa Kento,
Lawrence Katya,
Feberova Natalie,
Hayashi Miwa,
Jia Rizhe,
Jin Maggie,
Leha Emily,
Powter Morgan,
Shen Delphine Jiameng,
Walker Samuel,
Korneluk Robert
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.04464
Subject(s) - xiap , inhibitor of apoptosis , oncolytic virus , apoptosis , caspase , microbiology and biotechnology , cancer cell , immune system , biology , chemistry , cancer research , biochemistry , programmed cell death , immunology , cancer , genetics
X‐linked inhibitor of apoptosis protein (XIAP) is a key prosurvival protein that blocks apoptosis by inhibiting both the intrinsic and extrinsic pathways. Released by the mitochondria when under stress, XIAP is a homodimer, with 2 sets of repeating type I and type II baculoviral IAP domains: BIR1, BIR2 and BIR3, and RING. XIAP has a capacity to block apoptosis by directly inhibiting caspases 3,7 and 9. Second mitochondria‐derived activator of caspases (Smac) is a 184 amino acid chain. Smac antagonizes XIAP by attaching to the BIR3 domain inhibiting the binding of caspase‐9. Synthetic Smac mimetics (SMs) have been designed to duplicate the N‐terminal tetrapeptide (AVPI) or the IAP‐binding motif (IBM). Our model aims to show two BIR3 domain of a homodimer XIAP, bound to the IAP‐binding motif (IBM) of a Smac dimer. Selective antagonism of XIAP, specifically the BIR3 by Smac/SMs or monotherapy is not enough to kill cancer cells, however, it could be combined with immunotherapy, specifically virotherapy. This tricks the immune system to think that the cancer cells have a virus, which stimulates the immune antiviral response and creates an overproduction of immune cells known as a “cytokine storm”, to kill cancer cells. Support or Funding Information The Ashbury College MSOE Center for BioMolecular Modeling SMART Team used 3D modeling and printing technology to examine structure‐function relationships between Smac and BIR3 of XIAP.