Cell Stress and Chaperones

, Volume 15, Issue 5, pp 497–508 | Cite as

IRE1α controls cyclin A1 expression and promotes cell proliferation through XBP-1

  • Jeffery A. Thorpe
  • Steven R. SchwarzeEmail author
Original Paper


IRE1 is a conserved dual endoribonuclease/protein kinase that is indispensable for directing the endoplasmic reticulum (ER) stress response in yeast, flies, and worms. In mammalian systems, however, the precise biological activities carried out by IRE1α are unclear. Here, molecular and chemical genetic approaches were used to control IRE1 activity in a number of prostate cancer cell lines and the resulting impact on gene transcription, cell survival, and proliferation was examined. Modulating IRE1α activity had no transcriptional effect on the induction of genes classically associated with the ER stress response (Grp78 and CHOP) or cell survival when confronted with ER stress agents. Rather, IRE1α activity was positively correlated to proliferation. Since Xbp-1 mRNA is the sole known substrate for IRE1 endoribonuclease activity, the role of this transcription factor in mediating proliferation was examined. Repressing total Xbp-1 levels by siRNA techniques effectively slowed proliferation. In an effort to identify IRE1/XBP-1 targets responsible for the cell cycle response, genome-wide differential mRNA expression analysis was performed. Consistent with its ability to sense ER stress, IRE1α induction led to an enrichment of ER-Golgi, plasma membrane, and secretory gene products. An increase in cyclin A1 expression was the only differentially expressed cell cycle regulatory gene found. Greater cyclin A protein levels were consistently observed in cells with active IRE1α and were dependent on XBP-1. We conclude that IRE1α activity controls a subset of the ER stress response and mediates proliferation through tight control of Xbp-1 splicing.


ER stress Proliferation Cyclin A IRE1 XBP-1 



This work was supported by the New York Academy of Medicine (SRS).

Supplementary material

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  1. Bechill J, Chen Z, Brewer JW, Baker SC (2006) Mouse hepatitis virus infection activates the Ire1/XBP1 pathway of the unfolded protein response. Adv Exp Med Biol 581:139–144CrossRefPubMedGoogle Scholar
  2. Bluher M, Michael MD, Peroni OD, Ueki K, Carter N, Kahn BB, Kahn CR (2002) Adipose tissue selective insulin receptor knockout protects against obesity and obesity-related glucose intolerance. Dev Cell 3:25–38CrossRefPubMedGoogle Scholar
  3. Breckenridge DG, Germain M, Mathai JP, Nguyen M, Shore GC (2003) Regulation of apoptosis by endoplasmic reticulum pathways. Oncogene 22:8608–8618CrossRefPubMedGoogle Scholar
  4. Brostrom CO, Brostrom MA (1998) Regulation of translational initiation during cellular responses to stress. Prog Nucleic Acid Res Mol Biol 58:79–125CrossRefPubMedGoogle Scholar
  5. Cox JS, Shamu CE, Walter P (1993) Transcriptional induction of genes encoding endoplasmic reticulum resident proteins requires a transmembrane protein kinase. Cell 73:1197–1206CrossRefPubMedGoogle Scholar
  6. Drogat B, Auguste P, Nguyen DT, Bouchecareilh M, Pineau R, Nalbantoglu J, Kaufman RJ, Chevet E, Bikfalvi A, Moenner M (2007) IRE1 signaling is essential for ischemia-induced vascular endothelial growth factor-A expression and contributes to angiogenesis and tumor growth in vivo. Cancer Res 67:6700–6707CrossRefPubMedGoogle Scholar
  7. Ferri KF, Kroemer G (2001) Organelle-specific initiation of cell death pathways. Nat Cell Biol 3:E255–E263CrossRefPubMedGoogle Scholar
  8. Gregor MG, Hotamisligil GS (2007) Adipocyte stress: the endoplasmic reticulum and metabolic disease. J Lipid Res 48:1905–1914CrossRefPubMedGoogle Scholar
  9. Hampton RY (2002) ER-associated degradation in protein quality control and cellular regulation. Curr Opin Cell Biol 14:476–482CrossRefPubMedGoogle Scholar
  10. Harding HP, Calfon M, Urano F, Novoa I, Ron D (2002) Transcriptional and translational control in the mammalian unfolded protein response. Annu Rev Cell Dev Biol 18:575–599CrossRefPubMedGoogle Scholar
  11. Hollien J, Weissman JS (2006) Decay of endoplasmic reticulum-localized mRNAs during the unfolded protein response. Science 313:104–107CrossRefPubMedGoogle Scholar
  12. Hu P, Han Z, Couvillon AD, Kaufman RJ, Exton JH (2006) Autocrine tumor necrosis factor alpha links endoplasmic reticulum stress to the membrane death receptor pathway through IRE1alpha-mediated NF-kappaB activation and down-regulation of TRAF2 expression. Mol Cell Biol 26:3071–3084CrossRefPubMedGoogle Scholar
  13. Jarosch E, Lenk U, Sommer T (2003) Endoplasmic reticulum-associated protein degradation. Int Rev Cytol 223:39–81CrossRefPubMedGoogle Scholar
  14. Kaneko M, Ishiguro M, Niinuma Y, Uesugi M, Nomura Y (2002) Human HRD1 protects against ER stress-induced apoptosis through ER-associated degradation. FEBS Lett 532:147–152CrossRefPubMedGoogle Scholar
  15. Kaufman RJ (1999) Stress signaling from the lumen of the endoplasmic reticulum: coordination of gene transcriptional and translational controls. Genes Dev 13:1211–1233CrossRefPubMedGoogle Scholar
  16. Koong AC, Chauhan V, Romero-Ramirez L (2006) Targeting XBP-1 as a novel anti-cancer strategy. Cancer Biol Ther 5:756–759PubMedGoogle Scholar
  17. Lacroix M, Leclercq G (2004) About GATA3, HNF3A, and XBP1, three genes co-expressed with the oestrogen receptor-alpha gene (ESR1) in breast cancer. Mol Cell Endocrinol 219:1–7CrossRefPubMedGoogle Scholar
  18. Lee AH, Iwakoshi NN, Glimcher LH (2003a) XBP-1 regulates a subset of endoplasmic reticulum resident chaperone genes in the unfolded protein response. Mol Cell Biol 23:7448–7459CrossRefPubMedGoogle Scholar
  19. Lee AJ, Cai MX, Thomas PE, Conney AH, Zhu BT (2003b) Characterization of the oxidative metabolites of 17beta-estradiol and estrone formed by 15 selectively expressed human cytochrome p450 isoforms. Endocrinology 144:3382–3398CrossRefPubMedGoogle Scholar
  20. Lin JH, Li H, Yasumura D, Cohen HR, Zhang C, Panning B, Shokat KM, Lavail MM, Walter P (2007) IRE1 signaling affects cell fate during the unfolded protein response. Science 318:944–949CrossRefPubMedGoogle Scholar
  21. Mori K (2000) Tripartite management of unfolded proteins in the endoplasmic reticulum. Cell 101:451–454CrossRefPubMedGoogle Scholar
  22. Mori K, Ma W, Gething MJ, Sambrook J (1993) A transmembrane protein with a cdc2+/CDC28-related kinase activity is required for signaling from the ER to the nucleus. Cell 74:743–756CrossRefPubMedGoogle Scholar
  23. Morrison TB, Weis JJ, Wittwer CT (1998) Quantification of low-copy transcripts by continuous SYBR Green I monitoring during amplification. Biotechniques 24:954–958 960, 962PubMedGoogle Scholar
  24. Mulvey M, Arias C, Mohr I (2007) Maintenance of endoplasmic reticulum (ER) homeostasis in herpes simplex virus type 1-infected cells through the association of a viral glycoprotein with PERK, a cellular ER stress sensor. J Virol 81:3377–3390CrossRefPubMedGoogle Scholar
  25. Niwa M, Patil CK, DeRisi J, Walter P (2005) Genome-scale approaches for discovering novel nonconventional splicing substrates of the Ire1 nuclease. Genome Biol 6:R3CrossRefPubMedGoogle Scholar
  26. Ozcan U, Cao Q, Yilmaz E, Lee AH, Iwakoshi NN, Ozdelen E, Tuncman G, Gorgun C, Glimcher LH, Hotamisligil GS (2004) Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes. Science 306:457–461CrossRefPubMedGoogle Scholar
  27. Papa FR, Zhang C, Shokat K, Walter P (2003) Bypassing a kinase activity with an ATP-competitive drug. Science 302:1533–1537CrossRefPubMedGoogle Scholar
  28. Peterson FC, Thorpe JA, Harder AG, Volkman BF, Schwarze SR (2006) Structural determinants involved in the regulation of CXCL14/BRAK expression by the 26 S proteasome. J Mol Biol 363:813–822CrossRefPubMedGoogle Scholar
  29. Plemper RK, Wolf DH (1999) Retrograde protein translocation: ERADication of secretory proteins in health and disease. Trends Biochem Sci 24:266–270CrossRefPubMedGoogle Scholar
  30. Pottenger LH, Jefcoate CR (1990) Characterization of a novel cytochrome P450 from the transformable cell line, C3H/10T1/2. Carcinogenesis 11:321–327CrossRefPubMedGoogle Scholar
  31. Rao RV, Ellerby HM, Bredesen DE (2004) Coupling endoplasmic reticulum stress to the cell death program. Cell Death Differ 11:372–380CrossRefPubMedGoogle Scholar
  32. Rutkowski DT, Kaufman RJ (2004) A trip to the ER: coping with stress. Trends Cell Biol 14:20–28CrossRefPubMedGoogle Scholar
  33. Schroder M, Kaufman RJ (2005) The mammalian unfolded protein response. Annu Rev Biochem 74:739–789CrossRefPubMedGoogle Scholar
  34. Schwarze SR, Fu VX, Jarrard DF (2003) Cdc37 enhances proliferation and is necessary for normal human prostate epithelial cell survival. Cancer Res 63:4614–4619PubMedGoogle Scholar
  35. Shamu CE, Walter P (1996) Oligomerization and phosphorylation of the Ire1p kinase during intracellular signaling from the endoplasmic reticulum to the nucleus. Embo J 15:3028–3039PubMedGoogle Scholar
  36. Shang J (2005) Quantitative measurement of events in the mammalian unfolded protein response. Methods 35:390–394CrossRefPubMedGoogle Scholar
  37. Shen X, Ellis RE, Sakaki K, Kaufman RJ (2005) Genetic interactions due to constitutive and inducible gene regulation mediated by the unfolded protein response in C. elegans. PLoS Genet 1:e37CrossRefPubMedGoogle Scholar
  38. Shuda M, Kondoh N, Imazeki N, Tanaka K, Okada T, Mori K, Hada A, Arai M, Wakatsuki T, Matsubara O, Yamamoto N, Yamamoto M (2003) Activation of the ATF6, XBP1 and grp78 genes in human hepatocellular carcinoma: a possible involvement of the ER stress pathway in hepatocarcinogenesis. J Hepatol 38:605–614CrossRefPubMedGoogle Scholar
  39. Thorpe JA, Christian PA, Schwarze SR (2008) Proteasome inhibition blocks caspase-8 degradation and sensitizes prostate cancer cells to death receptor-mediated apoptosis. Prostate 68:200–209CrossRefPubMedGoogle Scholar
  40. Tirasophon W, Lee K, Callaghan B, Welihinda A, Kaufman RJ (2000) The endoribonuclease activity of mammalian IRE1 autoregulates its mRNA and is required for the unfolded protein response. Genes Dev 14:2725–2736CrossRefPubMedGoogle Scholar
  41. Tirosh B, Iwakoshi NN, Glimcher LH, Ploegh HL (2006) Rapid turnover of unspliced Xbp-1 as a factor that modulates the unfolded protein response. J Biol Chem 281:5852–5860CrossRefPubMedGoogle Scholar
  42. Welihinda AA, Kaufman RJ (1996) The unfolded protein response pathway in Saccharomyces cerevisiae. Oligomerization and trans-phosphorylation of Ire1p (Ern1p) are required for kinase activation. J Biol Chem 271:18181–18187CrossRefPubMedGoogle Scholar
  43. Wittwer CT, Herrmann MG, Moss AA, Rasmussen RP (1997) Continuous fluorescence monitoring of rapid cycle DNA amplification. Biotechniques 22(130–131):134–138Google Scholar
  44. Wu J, Rutkowski DT, Dubois M, Swathirajan J, Saunders T, Wang J, Song B, Yau GD, Kaufman RJ (2007) ATF6alpha optimizes long-term endoplasmic reticulum function to protect cells from chronic stress. Dev Cell 13:351–364CrossRefPubMedGoogle Scholar
  45. Yamamoto K, Sato T, Matsui T, Sato M, Okada T, Yoshida H, Harada A, Mori K (2007) Transcriptional induction of mammalian ER quality control proteins is mediated by single or combined action of ATF6alpha and XBP1. Dev Cell 13:365–376CrossRefPubMedGoogle Scholar
  46. Yang R, Muller C, Huynh V, Fung YK, Yee AS, Koeffler HP (1999) Functions of cyclin A1 in the cell cycle and its interactions with transcription factor E2F–1 and the Rb family of proteins. Mol Cell Biol 19:2400–2407PubMedGoogle Scholar
  47. Yoshida H, Matsui T, Yamamoto A, Okada T, Mori K (2001) XBP1 mRNA is induced by ATF6 and spliced by IRE1 in response to ER stress to produce a highly active transcription factor. Cell 107:881–891CrossRefPubMedGoogle Scholar
  48. Yoshida H, Oku M, Suzuki M, Mori K (2006) pXBP1(U) encoded in XBP1 pre-mRNA negatively regulates unfolded protein response activator pXBP1(S) in mammalian ER stress response. J Cell Biol 172:565–575CrossRefPubMedGoogle Scholar
  49. Yu CY, Hsu YW, Liao CL, Lin YL (2006) Flavivirus infection activates the XBP1 pathway of the unfolded protein response to cope with endoplasmic reticulum stress. J Virol 80:11868–11880CrossRefPubMedGoogle Scholar

Copyright information

© Cell Stress Society International 2009

Authors and Affiliations

  1. 1.Markey Cancer Center and Department of Molecular and Cellular BiochemistryUniversity of KentuckyLexingtonUSA

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