XIAP
Template:PBB X-linked inhibitor of apoptosis protein (XIAP), also known as inhibitor of apoptosis protein 3 (IAP3) and baculoviral IAP repeat-containing protein 4 (BIRC), is a protein that in humans is encoded by the XIAP gene.[1][2]
XIAP is a member of the inhibitor of apoptosis family of proteins (IAP). IAPs were initially identified in baculoviruses, but XIAP is one of the homologous proteins found in mammals.[3] It is so called because it was first discovered by a 273 base pair site on the X chromosome.[1] The protein is also called human IAP-like Protein (hILP), because it is not as well conserved as the human IAPS: hIAP-1 and hIAP-2.[1][4] XIAP is the most potent human IAP protein currently identified.[5]
Discovery
Neuronal apoptosis inhibitor protein (NAIP) was the first homolog to baculoviral IAPs that was identified in humans.[1] With the sequencing data of NIAP, the gene sequence for a RING zinc-finger domain was discovered at site Xq24-25.[1] Using PCR and cloning, three BIR domains and a RING finger were found on the protein, which became known as X-linked Inhibitor of Apoptosis Protein. The transcript size of Xiap is 9.0kb, with an open reading frame of 1.8kb.[1] Xiap mRNA has been observed in all human adult and fetal tissues "except peripheral blood leukocytes".[1] The XIAP sequences led to the discovery of other members of the IAP family.
Structure
XIAP consists of three major types of structural elements (domains). Firstly, there is the baculoviral IAP repeat (BIR) domain consisting of approximately 70 amino acids, which characterizes all IAP.[5] Secondly, there is a UBA domain, which allows XIAP to bind to ubiquitin. Thirdly, there is a zinc-binding domain, or a “carboxy-terminal RING Finger”.[4] XIAP has been characterized with three amino-terminal BIR domains followed by one UBA domain and finally one RING domain.[6] Between the BIR-1 and BIR-2 domains, there is a linker-BIR-2 region that is thought to contain the only element that comes into contact with the caspase molecule to form the XIAP/Caspase-7 complex.[7]
Function
XIAP stops apoptotic cell death that is induced either by viral infection or by overproduction of caspases. caspases are the enzymes primarily responsible for cell death.[4] XIAP binds to and inhibits caspase 3, 7 and 9.[5] The BIR2 domain of XIAP inhibits caspase 3 and 7, while BIR3 binds to and inhibits caspase 9.[5] The RING domain utilizes E3 ubiquitin ligase activity and enables IAPs to catalyze ubiquination of self, caspase-3, or caspase-7 by degradation via proteasome activity.[8] However, mutations affecting the RING Finger do not significantly affect apoptosis, indicating that the BIR domain is sufficient for the protein’s function.[4] When inhibiting caspase-3 and caspase-7 activity, the BIR2 domain of XIAP binds to the active-site substrate groove, blocking access of the normal protein substrate that would result in apoptosis.[8][9]
Caspases are activated by cytochrome c, which is released into the cytosol by dysfunctioning mitochondria.[4] Studies show that XIAP does not directly affect cytochrome c.[4]
XIAP distinguishes itself from the other human IAPs because it is able to effectively prevent cell death due to "TNF-α, Fas, UV light, and genotoxic agents".[4]
The second BIR domain of XIAP can be shown binding to caspase 3 where a protein substrate would normally bind during aptosis. By blocking this binding, XIAP inhibits apoptosis.
Inhibiting XIAP
XIAP is inhibited by DIABLO (Smac) and HTRA2 (Omi), two death-signaling proteins released into the cytoplasm by the mitochondria.[6] Smac/DIABLO, a mitochondrial protein and negative regulator of XIAP, can enhance apoptosis by binding to XIAP and preventing it from binding to caspases. This allows normal caspase activity to proceed. The binding process of Smac/DIABLO to XIAP and caspase release requires a conserved tetrapeptide motif.[8]
Clinical significance
Deregulation of XIAP can result in “cancer, neurodegenerative disorders, and autoimmunity”.[6] High proportions of XIAP may function as a tumor marker.[5] In the development of lung cancer NCI-H460, the overexpression of XIAP not only inhibits caspase, but also stops the activity of cytochrome c (Apoptosis). In developing prostate cancer, XIAP is one of four IAPs overexpressed in the prostatic epithelium, indicating that a molecule that inhibits all IAPs may be necessary for effective treatment.[10] Apoptotic regulation is an extremely important biological function, as evidenced by "the conservation of the IAPs from humans to Drosophila".[1]
Mutations in the XIAP gene can result in a severe and rare type of inflammatory bowel disease.[11] Defects in the XIAP gene can also result in an extremely rare condition called X-linked lymphoproliferative disease.[11]
Interactions
XIAP has been shown to interact with:
References
- ^ a b c d e f g h Liston P, Roy N, Tamai K, Lefebvre C, Baird S, Cherton-Horvat G, Farahani R, McLean M, Ikeda JE, MacKenzie A, Korneluk RG (1996). "Suppression of apoptosis in mammalian cells by NAIP and a related family of IAP genes". Nature. 379 (6563): 349–53. doi:10.1038/379349a0. PMID 8552191.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Holcik M, Korneluk RG (2000). "Functional Characterization of the X-Linked Inhibitor of Apoptosis (XIAP) Internal Ribosome Entry Site Element: Role of La Autoantigen in XIAP Translation". Mol. Cell. Biol. 20 (13): 4648–57. doi:10.1128/MCB.20.13.4648-4657.2000. PMC 85872. PMID 10848591.
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ignored (help) - ^ a b c d e f g Duckett CS, Li F, Wang Y, Tomaselli KJ, Thompson CB, Armstrong RC (1 January 1998). "Human IAP-Like Protein Regulates Programmed Cell Death Downstream of Bcl-xL and Cytochrome c". Mol. Cell. Biol. 18 (1): 608–15. PMC 121528. PMID 9418907.
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: CS1 maint: multiple names: authors list (link) - ^ a b c d e Deveraux QL, Reed JC (1999). "IAP family proteins – suppressors of apoptosis". Genes Dev. 13 (3): 239–52. doi:10.1101/gad.13.3.239. PMID 9990849.
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ignored (help) Cite error: The named reference "Reed" was defined multiple times with different content (see the help page). - ^ a b c Wilkinson JC, Cepero E, Boise LH, Duckett CS (2004). "Upstream Regulatory Role for XIAP in Receptor-Mediated Apoptosis". Mol. Cell. Biol. 24 (16): 7003–14. doi:10.1128/MCB.24.16.7003-7014.2004. PMC 479745. PMID 15282301.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Huang Y, Park YC, Rich RL, Segal D, Myszka DG, Wu H (2001). "Structural basis of caspase inhibition by XIAP: differential roles of the linker versus the BIR domain". Cell. 104 (5): 781–90. doi:10.1016/S0092-8674(01)00273-2. PMID 11257231.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b c Gewies A (2003). "Introduction to Apoptosis" (PDF). CellDeath.de. Retrieved 2008-08-12.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Watson RW, Fitzpatrick JM (2005). "Targeting apoptosis in prostate cancer: focus on caspases and inhibitors of apoptosis proteins". BJU Int. 96 Suppl 2: 30–4. doi:10.1111/j.1464-410X.2005.05944.x. PMID 16359436.
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ignored (help) - ^ a b Worthey EA, Mayer AN, Syverson GD; et al. (2011). "Making a definitive diagnosis: Successful clinical application of whole exome sequencing in a child with intractable inflammatory bowel disease" (PDF). Genet Med. 13 (1): 255–62. doi:10.1097/GIM.0b013e3182088158. PMID 21173700.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b Sanna MG, da Silva Correia J, Luo Y, Chuang B, Paulson LM, Nguyen B, Deveraux QL, Ulevitch RJ (2002). "ILPIP, a novel anti-apoptotic protein that enhances XIAP-mediated activation of JNK1 and protection against apoptosis". J. Biol. Chem. 277 (34): 30454–62. doi:10.1074/jbc.M203312200. PMID 12048196.
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ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ a b Riedl SJ, Renatus M, Schwarzenbacher R, Zhou Q, Sun C, Fesik SW, Liddington RC, Salvesen GS (2001). "Structural basis for the inhibition of caspase-3 by XIAP". Cell. 104 (5): 791–800. doi:10.1016/S0092-8674(01)00274-4. PMID 11257232.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b Deveraux QL, Takahashi R, Salvesen GS, Reed JC (1997). "X-linked IAP is a direct inhibitor of cell-death proteases". Nature. 388 (6639): 300–4. doi:10.1038/40901. PMID 9230442.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b Suzuki Y, Nakabayashi Y, Nakata K, Reed JC, Takahashi R (2001). "X-linked inhibitor of apoptosis protein (XIAP) inhibits caspase-3 and -7 in distinct modes". J. Biol. Chem. 276 (29): 27058–63. doi:10.1074/jbc.M102415200. PMID 11359776.
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ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Suzuki Y, Nakabayashi Y, Takahashi R (2001). "Ubiquitin-protein ligase activity of X-linked inhibitor of apoptosis protein promotes proteasomal degradation of caspase-3 and enhances its anti-apoptotic effect in Fas-induced cell death". Proc. Natl. Acad. Sci. U.S.A. 98 (15): 8662–7. doi:10.1073/pnas.161506698. PMC 37492. PMID 11447297.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Silke J, Hawkins CJ, Ekert PG, Chew J, Day CL, Pakusch M, Verhagen AM, Vaux DL (2002). "The anti-apoptotic activity of XIAP is retained upon mutation of both the caspase 3– and caspase 9–interacting sites". J. Cell Biol. 157 (1): 115–24. doi:10.1083/jcb.200108085. PMC 2173256. PMID 11927604.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP, Vidal M (2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173–8. doi:10.1038/nature04209. PMID 16189514.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b Davoodi J, Lin L, Kelly J, Liston P, MacKenzie AE (2004). "Neuronal apoptosis-inhibitory protein does not interact with Smac and requires ATP to bind caspase-9". J. Biol. Chem. 279 (39): 40622–8. doi:10.1074/jbc.M405963200. PMID 15280366.
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ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Deveraux QL, Roy N, Stennicke HR, Van Arsdale T, Zhou Q, Srinivasula SM, Alnemri ES, Salvesen GS, Reed JC (1998). "IAPs block apoptotic events induced by caspase-8 and cytochrome c by direct inhibition of distinct caspases". EMBO J. 17 (8): 2215–23. doi:10.1093/emboj/17.8.2215. PMC 1170566. PMID 9545235.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Richter BW, Mir SS, Eiben LJ, Lewis J, Reffey SB, Frattini A, Tian L, Frank S, Youle RJ, Nelson DL, Notarangelo LD, Vezzoni P, Fearnhead HO, Duckett CS (2001). "Molecular Cloning of ILP-2, a Novel Member of the Inhibitor of Apoptosis Protein Family". Mol. Cell. Biol. 21 (13): 4292–301. doi:10.1128/MCB.21.13.4292-4301.2001. PMC 87089. PMID 11390657.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b Verhagen AM, Silke J, Ekert PG, Pakusch M, Kaufmann H, Connolly LM, Day CL, Tikoo A, Burke R, Wrobel C, Moritz RL, Simpson RJ, Vaux DL (2002). "HtrA2 promotes cell death through its serine protease activity and its ability to antagonize inhibitor of apoptosis proteins". J. Biol. Chem. 277 (1): 445–54. doi:10.1074/jbc.M109891200. PMID 11604410.
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ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Song Z, Yao X, Wu M (2003). "Direct interaction between survivin and Smac/DIABLO is essential for the anti-apoptotic activity of survivin during taxol-induced apoptosis". J. Biol. Chem. 278 (25): 23130–40. doi:10.1074/jbc.M300957200. PMID 12660240.
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ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Verhagen AM, Ekert PG, Pakusch M, Silke J, Connolly LM, Reid GE, Moritz RL, Simpson RJ, Vaux DL (2000). "Identification of DIABLO, a mammalian protein that promotes apoptosis by binding to and antagonizing IAP proteins". Cell. 102 (1): 43–53. doi:10.1016/S0092-8674(00)00009-X. PMID 10929712.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Hegde R, Srinivasula SM, Datta P, Madesh M, Wassell R, Zhang Z, Cheong N, Nejmeh J, Fernandes-Alnemri T, Hoshino S, Alnemri ES (2003). "The polypeptide chain-releasing factor GSPT1/eRF3 is proteolytically processed into an IAP-binding protein". J. Biol. Chem. 278 (40): 38699–706. doi:10.1074/jbc.M303179200. PMID 12865429.
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ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Jordan BW, Dinev D, LeMellay V, Troppmair J, Gotz R, Wixler L, Sendtner M, Ludwig S, Rapp UR (2001). "Neurotrophin receptor-interacting mage homologue is an inducible inhibitor of apoptosis protein-interacting protein that augments cell death". J. Biol. Chem. 276 (43): 39985–9. doi:10.1074/jbc.C100171200. PMID 11546791.
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ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Winsauer G, Resch U, Hofer-Warbinek R, Schichl YM, de Martin R (2008). "XIAP regulates bi-phasic NF-kappaB induction involving physical interaction and ubiquitination of MEKK2". Cell. Signal. 20 (11): 2107–12. doi:10.1016/j.cellsig.2008.08.004. PMID 18761086.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Yamaguchi K, Nagai S, Ninomiya-Tsuji J, Nishita M, Tamai K, Irie K, Ueno N, Nishida E, Shibuya H, Matsumoto K (1999). "XIAP, a cellular member of the inhibitor of apoptosis protein family, links the receptors to TAB1-TAK1 in the BMP signaling pathway". EMBO J. 18 (1): 179–87. doi:10.1093/emboj/18.1.179. PMC 1171113. PMID 9878061.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Liston P, Fong WG, Kelly NL, Toji S, Miyazaki T, Conte D, Tamai K, Craig CG, McBurney MW, Korneluk RG (2001). "Identification of XAF1 as an antagonist of XIAP anti-Caspase activity". Nat. Cell Biol. 3 (2): 128–33. doi:10.1038/35055027. PMID 11175744.
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Further reading
- Lacasse EC, Kandimalla ER, Winocour P; et al. (2006). "Application of XIAP antisense to cancer and other proliferative disorders: development of AEG35156/ GEM640". Ann. N. Y. Acad. Sci. 1058: 215–34. doi:10.1196/annals.1359.032. PMID 16394139.
{{cite journal}}
: Explicit use of et al. in:|author=
(help)CS1 maint: multiple names: authors list (link) - Eckelman BP, Salvesen GS, Scott FL (2006). "Human inhibitor of apoptosis proteins: why XIAP is the black sheep of the family". EMBO Rep. 7 (10): 988–94. doi:10.1038/sj.embor.7400795. PMC 1618369. PMID 17016456.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)