Forkhead box protein O1A ; Forkhead in rhabdomyosarcoma ; Foxo1a
Categories
Elisa
Function
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[GA]TTTTG-3' and the related Daf-16 family binding element (DBE) with consensus sequence 5'-TT[GA]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.
Specificity
Natural and recombinant Rat Forkhead box protein O1
Subcellular Location
Cytoplasm Nucleus Shuttles between the cytoplasm and nucleus. Largely nuclear in unstimulated cells. In osteoblasts, colocalizes with ATF4 and RUNX2 in the nucleus. Insulin-induced phosphorylation at Ser-250 by PKB/AKT1 leads, via stimulation of Thr-24 phosphorylation, to binding of 14-3-3 proteins and nuclear export to the cytoplasm where it is degraded by the ubiquitin-proteosomal pathway. Phosphorylation at Ser-243 by CDK1 disrupts binding of 14-3-3 proteins and promotes nuclear accumulation. Phosphorylation by NLK results in nuclear export. Translocates to the nucleus upon oxidative stress-induced phosphorylation at Ser-206 by STK4/MST1. SGK1-mediated phosphorylation also results in nuclear translocation. Retained in the nucleus under stress stimuli including oxidative stress, nutrient deprivation or nitric oxide. Retained in the nucleus on methylation.
Interacts with LRPPRC. Interacts with RUNX2; the interaction inhibits RUNX2 transcriptional activity and mediates the IGF1/insulin-dependent BGLAP expression in osteoblasts Interacts with PPP2R1A; the interaction regulates the dephosphorylation of FOXO1 at Thr-24 and Ser-250 leading to its nuclear import. Interacts with NLK. Interacts with SIRT1; the interaction results in the deacetylation of FOXO1 leading to activation of FOXO1-mediated transcription of genes involved in DNA repair and stress resistance. Binds to CDK1. Interacts with the 14-3-3 proteins, YWHAG and YWHAZ; the interactions require insulin-stimulated phosphorylation on Thr-24, promote nuclear exit and loss of transcriptional activity. Interacts with SKP2; the interaction ubiquitinates FOXO1 leading to its proteosomal degradation. The interaction requires the presence of KRIT1. Interacts (via the C-terminal half) with ATF4 (via its DNA binding domain); the interaction occurs in osteoblasts, regulates glucose homeostasis via suppression of beta-cell proliferation and subsequent decrease in insulin production. Interacts with PRMT1; the interaction methylates FOXO1, prevents PKB/AKT1 phosphorylation and retains FOXO1 in the nucleus. Interacts with EP300 and CREBBP; the interactions acetylate FOXO1.