5dui

Structural highlights

Disease

[FOXO1_HUMAN] Defects in FOXO1 are a cause of rhabdomyosarcoma type 2 (RMS2) [MIM:268220]. It is a form of rhabdomyosarcoma, a highly malignant tumor of striated muscle derived from primitive mesenchimal cells and exhibiting differentiation along rhabdomyoblastic lines. Rhabdomyosarcoma is one of the most frequently occurring soft tissue sarcomas and the most common in children. It occurs in four forms: alveolar, pleomorphic, embryonal and botryoidal rhabdomyosarcomas. Note=Chromosomal aberrations involving FOXO1 are found in rhabdomyosarcoma. Translocation (2;13)(q35;q14) with PAX3 and translocation t(1;13)(p36;q14) with PAX7. The resulting protein is a transcriptional activator.

Function

[FOXO1_HUMAN] Transcription factor that is the main target of insulin signaling and regulates metabolic homeostasis in response to oxidative stress. Binds to the insulin response element (IRE) with consensus sequence 5'-TT[G/A]TTTTG-3' and the related Daf-16 family binding element (DBE) with consensus sequence 5'-TT[G/A]TTTAC-3'. Activity suppressed by insulin. Main regulator of redox balance and osteoblast numbers and controls bone mass. Orchestrates the endocrine function of the skeleton in regulating glucose metabolism. Acts syngernistically with ATF4 to suppress osteocalcin/BGLAP activity, increasing glucose levels and triggering glucose intolerance and insulin insensitivity. Also suppresses the transcriptional activity of RUNX2, an upstream activator of osteocalcin/BGLAP. In hepatocytes, promotes gluconeogenesis by acting together with PPARGC1A to activate the expression of genes such as IGFBP1, G6PC and PPCK1. Important regulator of cell death acting downstream of CDK1, PKB/AKT1 and SKT4/MST1. Promotes neural cell death. Mediates insulin action on adipose. Regulates the expression of adipogenic genes such as PPARG during preadipocyte differentiation and, adipocyte size and adipose tissue-specific gene expression in response to excessive calorie intake. Regulates the transcriptional activity of GADD45A and repair of nitric oxide-damaged DNA in beta-cells.^{[1] [2] [3] [4] [5] [6] [7]}

References

1. ↑ Guo S, Rena G, Cichy S, He X, Cohen P, Unterman T. Phosphorylation of serine 256 by protein kinase B disrupts transactivation by FKHR and mediates effects of insulin on insulin-like growth factor-binding protein-1 promoter activity through a conserved insulin response sequence. J Biol Chem. 1999 Jun 11;274(24):17184-92. PMID:10358076
2. ↑ Zhang X, Gan L, Pan H, Guo S, He X, Olson ST, Mesecar A, Adam S, Unterman TG. Phosphorylation of serine 256 suppresses transactivation by FKHR (FOXO1) by multiple mechanisms. Direct and indirect effects on nuclear/cytoplasmic shuttling and DNA binding. J Biol Chem. 2002 Nov 22;277(47):45276-84. Epub 2002 Sep 12. PMID:12228231 doi:10.1074/jbc.M208063200
3. ↑ Daitoku H, Hatta M, Matsuzaki H, Aratani S, Ohshima T, Miyagishi M, Nakajima T, Fukamizu A. Silent information regulator 2 potentiates Foxo1-mediated transcription through its deacetylase activity. Proc Natl Acad Sci U S A. 2004 Jul 6;101(27):10042-7. Epub 2004 Jun 25. PMID:15220471 doi:10.1073/pnas.0400593101
4. ↑ Perrot V, Rechler MM. The coactivator p300 directly acetylates the forkhead transcription factor Foxo1 and stimulates Foxo1-induced transcription. Mol Endocrinol. 2005 Sep;19(9):2283-98. Epub 2005 May 12. PMID:15890677 doi:10.1210/me.2004-0292
5. ↑ Yuan Z, Becker EB, Merlo P, Yamada T, DiBacco S, Konishi Y, Schaefer EM, Bonni A. Activation of FOXO1 by Cdk1 in cycling cells and postmitotic neurons. Science. 2008 Mar 21;319(5870):1665-8. doi: 10.1126/science.1152337. PMID:18356527 doi:10.1126/science.1152337
6. ↑ Yuan Z, Lehtinen MK, Merlo P, Villen J, Gygi S, Bonni A. Regulation of neuronal cell death by MST1-FOXO1 signaling. J Biol Chem. 2009 Apr 24;284(17):11285-92. doi: 10.1074/jbc.M900461200. Epub 2009, Feb 16. PMID:19221179 doi:10.1074/jbc.M900461200
7. ↑ Valis K, Prochazka L, Boura E, Chladova J, Obsil T, Rohlena J, Truksa J, Dong LF, Ralph SJ, Neuzil J. Hippo/Mst1 stimulates transcription of the proapoptotic mediator NOXA in a FoxO1-dependent manner. Cancer Res. 2011 Feb 1;71(3):946-54. doi: 10.1158/0008-5472.CAN-10-2203. Epub, 2011 Jan 18. PMID:21245099 doi:10.1158/0008-5472.CAN-10-2203