| 1999 |
Akt (protein kinase B) directly phosphorylates FOXO1 (FKHR) in vitro and in vivo at three sites (Thr-24, Ser-256, Ser-319), leading to suppression of FOXO1-mediated transcriptional activation; mutation of all three sites to alanine renders FOXO1 resistant to Akt inhibition and causes apoptosis in a DNA-binding-dependent manner. |
In vitro kinase assay, co-transfection with active/inactive Akt, alanine-substitution mutagenesis, reporter gene assays, apoptosis assay |
The Journal of biological chemistry |
High |
10358014 10358075
|
| 1999 |
FOXO1 binds in vitro to the insulin-responsive sequence (IRS) in the IGFBP-1 promoter and activates transcription from IRS-containing reporter plasmids; Akt-mediated phosphorylation inhibits this transcriptional activity. |
In vitro DNA binding assay, luciferase reporter assay, co-transfection |
The Journal of biological chemistry |
High |
10358014 10358075
|
| 2001 |
FOXO1 confers insulin sensitivity onto glucose-6-phosphatase (G6P) expression in kidney epithelial cells; adenoviral transduction of FOXO1 restores insulin-mediated suppression of dexamethasone/cAMP-induced G6P expression, and dominant-negative FOXO1 partially inhibits G6P and PEPCK expression in primary hepatocytes, establishing FOXO1 as a mediator of insulin regulation of gluconeogenic gene expression. |
Adenoviral transduction, dominant-negative mutant expression, primary hepatocyte cultures, gene expression analysis |
The Journal of clinical investigation |
High |
11696581
|
| 2001 |
DYRK1A phosphorylates FOXO1 (FKHR) specifically at Ser-329 in vitro; this phosphorylation reduces FOXO1 nuclear abundance and transcriptional activity; DYRK1A and FOXO1 co-localize in discrete nuclear regions and can be co-immunoprecipitated, suggesting DYRK1A phosphorylates FOXO1 at Ser-329 in vivo. |
Purification of kinase from skeletal muscle, in vitro kinase assay, co-immunoprecipitation, nuclear co-localization, site-directed mutagenesis, reporter assay |
The Biochemical journal |
High |
11311120
|
| 2002 |
FOXO1-mediated inhibition of cell cycle progression and transformation requires transcriptional repression of D-type cyclins (Class III targets) rather than activation of insulin-response-sequence genes; chromatin immunoprecipitation confirmed direct FOXO1 occupancy at cyclin D promoters. |
Transcriptional profiling, chromatin immunoprecipitation (ChIP), functional cell-cycle and transformation assays |
Cancer cell |
High |
12150827
|
| 2003 |
Insulin-induced Akt-mediated phosphorylation of FOXO1 targets it for ubiquitination and proteasomal degradation; efficient ubiquitination requires both phosphorylation at the PKB consensus sites and cytoplasmic retention, establishing a two-step negative regulation (nuclear exclusion then proteasomal degradation). |
Proteasome inhibitor treatment, in vivo and in vitro ubiquitination assays, PI3K pathway inhibitors, phosphorylation-site mutants |
Proceedings of the National Academy of Sciences of the United States of America |
High |
13679577
|
| 2003 |
The androgen receptor (AR) directly interacts with FOXO1 through protein-protein interaction (carboxyl terminus of FOXO1, aa 350–655, with AR A/B region and ligand-binding domain), blocking FOXO1 DNA-binding activity and its ability to induce Fas ligand expression and apoptosis in an AKT-independent manner. |
In vivo and in vitro co-precipitation, domain-mapping, reporter gene assay, apoptosis/cell-cycle assays |
Molecular and cellular biology |
High |
12482965
|
| 2004 |
CK1 phosphorylates FOXO1a at Ser-322 and Ser-325 within a multisite phosphorylation domain in vivo; pharmacological inhibition of CK1 with D4476 specifically blocks these phosphorylations and attenuates IGF-1/insulin-induced nuclear exclusion of FOXO1a. |
Cell-permeable CK1 inhibitor (D4476), phospho-specific analysis, nuclear/cytoplasmic fractionation, H4IIE hepatoma cells |
EMBO reports |
High |
14710188
|
| 2004 |
Foxo1 is essential for normal vascular development; Foxo1-deficient mice die at embryonic day ~11 with severe defects in angiogenesis, and Foxo1-null endothelial cells derived from ES cells show aberrant morphological response to VEGF, indicating Foxo1 is required for proper endothelial cell response to VEGF signaling. |
Foxo1 knockout mice (embryonic lethal phenotype), ES-cell-derived endothelial cell differentiation assay, VEGF stimulation |
The Journal of biological chemistry |
High |
15184386
|
| 2004 |
SIRT1 (Sir2) binds and deacetylates FOXO1 at lysine residues (K242, K245, K262) that are acetylated by CBP, reversing the attenuation of FOXO1 transcriptional activity; SIRT1 is recruited to FOXO1 target promoters (MnSOD, p27kip1) and enhances their expression in a deacetylase-activity-dependent manner. |
Co-immunoprecipitation, in vitro deacetylation assay, ChIP, reporter assay, deacetylase-inactive mutants |
Proceedings of the National Academy of Sciences of the United States of America |
High |
15220471
|
| 2004 |
Foxo transcription factors (including Foxo1) drive atrogin-1/MAFbx ubiquitin ligase expression in skeletal muscle; constitutively active Foxo3 acts on the atrogin-1 promoter to cause transcription and dramatic muscle atrophy; dominant-negative Foxo or RNAi-mediated knockdown prevents atrogin-1 induction and muscle atrophy in vitro and in vivo. |
Constitutively active Foxo constructs, dominant-negative constructs, RNAi in mouse muscle in vivo, promoter reporter assay, myotube atrophy assay |
Cell |
High |
15109499
|
| 2005 |
FoxO1 protects pancreatic beta cells against oxidative stress by forming a complex with PML and SIRT1 to activate NeuroD and MafA transcription; acetylation of FoxO1 targets it to PML and prevents ubiquitin-dependent degradation, and constitutively nuclear FoxO1 in beta cells prevents hyperglycemia-induced suppression of MafA. |
Co-immunoprecipitation (FoxO1-PML-SIRT1 complex), acetylation-defective and acetylation-mimicking mutants, transgenic mice, in vivo MafA expression analysis |
Cell metabolism |
High |
16154098
|
| 2005 |
Acetylation of FOXO1 by CBP at Lys-242, Lys-245, and Lys-262 reduces its DNA-binding affinity by neutralizing positive charges required for DNA interaction; additionally, acetylation increases susceptibility of FOXO1 to Akt-mediated phosphorylation at Ser-253, and DNA binding inhibits PKB phosphorylation of FOXO1 in vitro. |
In vitro DNA binding assays, in vitro kinase assays, acetylation-mimicking and acetylation-deficient mutants, phosphorylation analysis |
Proceedings of the National Academy of Sciences of the United States of America |
High |
16076959
|
| 2005 |
Skp2, an oncogenic F-box protein, interacts with and ubiquitinates FOXO1 in an Akt phosphorylation (Ser-256)-dependent manner, promoting FOXO1 proteasomal degradation and abolishing its growth-inhibitory and pro-apoptotic functions. |
Co-immunoprecipitation, in vitro ubiquitination assay, phosphorylation-site mutants, cell proliferation/survival assays, mouse lymphoma model |
Proceedings of the National Academy of Sciences of the United States of America |
High |
15668399
|
| 2005 |
Foxo1 (and Foxo3a) overexpression inhibits endothelial cell migration and tube formation; Foxo1 specifically represses angiopoietin-2 expression and binds to the eNOS promoter to repress eNOS expression, establishing Foxo1 as a regulator of angiogenesis-related gene expression in endothelial cells. |
Constitutively active Foxo constructs, siRNA knockdown, gene expression profiling, ChIP on eNOS promoter, migration/tube formation assays |
The Journal of clinical investigation |
High |
16100571
|
| 2005 |
PAK1 (p21-activated kinase 1) directly interacts with FOXO1 (FKHR) and phosphorylates it in response to estrogen stimulation, causing perinuclear cytoplasmic retention and preventing FOXO1 from activating Fas ligand promoter transcription; dominant-negative PAK1 restores FOXO1 transcriptional activity. |
Co-immunoprecipitation, in vitro kinase assay (PAK1 phosphorylating FKHR), localization microscopy, reporter gene assay |
FEBS letters |
Medium |
12560069
|
| 2005 |
Beta-catenin directly binds FOXO transcription factors and enhances FOXO transcriptional activity in mammalian cells; this interaction is evolutionarily conserved (C. elegans BAR-1/DAF-16) and is enhanced under oxidative stress, establishing beta-catenin as a co-activator of FOXO-dependent stress response. |
Co-immunoprecipitation, reporter assay, C. elegans genetic epistasis, oxidative stress experiments |
Science |
High |
15905404
|
| 2005 |
FoxO1a directly activates transcription of the cyclic GMP-dependent protein kinase I (cGKI) gene; the resulting cGKI then phosphorylates FoxO1a and abolishes its DNA-binding activity, establishing an autoregulatory feedback loop that controls myoblast fusion. |
Reporter gene assay, phosphorylation assay (cGKI on FoxO1a), myoblast fusion assay |
Molecular and cellular biology |
Medium |
16107711
|
| 2006 |
Constitutively active FoxO1 in transgenic mouse liver increases gluconeogenic gene expression (PEPCK, G6Pase), suppresses glycolytic, pentose phosphate shunt, and lipogenic genes (including glucokinase and SREBP-1c), and impairs glucose tolerance; adenoviral FoxO1 in hepatocytes confirms direct regulation of these metabolic gene programs. |
Transgenic mice with liver-specific constitutively active FoxO1, gene array, adenoviral transduction of hepatocytes, metabolic phenotyping |
The Journal of biological chemistry |
High |
16492665
|
| 2006 |
FOXO1A cooperates with HoxA-10 to regulate decidual IGFBP-1 expression; co-immunoprecipitation and ChIP demonstrate physical association of FOXO1A with HoxA-11 and binding of both to the decidual prolactin promoter enhancer, forming a decidual-specific transcriptional complex that switches HoxA-11 from repressor to activator. |
Co-immunoprecipitation, ChIP, reporter gene assay, siRNA knockdown |
PloS one |
Medium |
19727442
|
| 2008 |
PRMT1 methylates FOXO1 at Arg-248 and Arg-250 within the Akt phosphorylation consensus motif; this arginine methylation directly blocks Akt-mediated phosphorylation of FOXO1 at Ser-253 in vitro and in vivo, preventing nuclear exclusion and proteasomal degradation, thereby promoting oxidative-stress-induced apoptosis. |
In vitro methylation assay, in vitro kinase assay, PRMT1 siRNA knockdown, polyubiquitination assay, apoptosis assay, phosphorylation-deficient mutants |
Molecular cell |
High |
18951090
|
| 2008 |
PGC-1alpha cooperates with FoxO1a and HNF-4alpha to drive selenoprotein P (SeP) promoter activity; PGC-1alpha enhances FoxO1a-stimulated SeP transcription through a FoxO-responsive element; insulin suppresses this axis, establishing FoxO1a as a component of the PGC-1alpha-regulated selenium homeostasis network. |
Reporter assay, promoter mutagenesis, adenoviral overexpression, primary rat hepatocytes, mRNA/protein analysis |
Hepatology |
Medium |
18972406
|
| 2010 |
FoxO1 promotes inflammation by enhancing TLR4-mediated signaling in macrophages; ChIP-Seq shows FoxO1 binds multiple enhancer-like elements within the Tlr4 gene and TLR4 pathway genes; TLR4 activation induces Akt which inactivates FoxO1, establishing a self-limiting inflammatory feedback loop. |
ChIP combined with massively parallel sequencing (ChIP-Seq), FoxO1 knockout macrophages, reporter assay, inflammatory cytokine measurements |
The EMBO journal |
High |
21045807
|
| 2010 |
TAK1-NLK (Nemo-like kinase) pathway phosphorylates FOXO1 at Pro-directed Ser/Thr residues in the transactivation domain; this phosphorylation inhibits FOXO1 transcriptional activity and causes nuclear exclusion independently of PI3K/Akt; NLK binds FOXO1 and this interaction is evolutionarily conserved in Drosophila. |
Co-immunoprecipitation, kinase assay (NLK on FOXO1), nuclear/cytoplasmic fractionation, siRNA knockdown of TAK1/NLK, FOXO target gene mRNA assay, PARP cleavage |
The Journal of biological chemistry |
Medium |
20061393
|
| 2010 |
Cytosolic FoxO1 mediates autophagy independently of its transcriptional activity; in response to oxidative stress or serum starvation, FoxO1 is acetylated by dissociation from SIRT2, and acetylated FoxO1 binds to Atg7 (an E1-like autophagy protein) to induce autophagy and cell death; this is associated with tumor suppressor activity. |
Co-immunoprecipitation (FoxO1-Atg7 interaction), transcription-deficient FoxO1 mutants, autophagy assays, SIRT2 interaction studies, xenograft tumor model |
Nature cell biology |
High |
20543840
|
| 2011 |
FoxO1 and SIRT1 regulate beta-cell responses to nitric oxide; FoxO1 translocates from cytoplasm to nucleus in response to nitric oxide and stimulates GADD45α expression for DNA repair; SIRT1 regulates this process—SIRT1 inhibition shifts FoxO1 from a protective (GADD45α/DNA repair) to a proapoptotic (PUMA/caspase-3) program. |
Nuclear translocation assay, gene expression analysis, SIRT1 pharmacological inhibitors, siRNA, caspase-3 cleavage assay |
The Journal of biological chemistry |
Medium |
21196578
|
| 2011 |
Hepatic deletion of Foxo1 (but not Foxo3 or Foxo4 alone) reduces blood glucose by decreasing gluconeogenic enzyme gene expression; combined deletion of Foxo1 and Foxo3 additionally increases hepatic lipid synthesis and secretion, demonstrating that Foxo1 specifically controls gluconeogenesis while Foxo3 regulates lipogenic gene expression. |
Liver-specific Cre/LoxP conditional knockout mice (individual and combined deletions), metabolic phenotyping, liver transcript analysis |
Endocrinology |
High |
22147007
|
| 2013 |
mTORC2 promotes inactivating phosphorylation of class IIa HDACs, leading to acetylation of FoxO1 (and FoxO3), which releases c-Myc from a suppressive miR-34c network to drive glycolytic reprogramming in glioblastoma; this is an Akt-independent mechanism linking mTORC2 to FoxO acetylation and cancer metabolism. |
mTORC2 genetic manipulation, HDAC phosphorylation/acetylation assays, FoxO acetylation analysis, c-Myc/miR-34c network analysis, glioblastoma patient samples |
Cell metabolism |
High |
24140020
|
| 2014 |
FOXO1/3 knockdown in vascular smooth muscle cells phenocopies PTEN deficiency by increasing Runx2 protein via decreased Runx2 ubiquitination, promoting vascular calcification; AKT activation causes FOXO1/3 nuclear exclusion, establishing a PTEN/AKT/FOXO1/3/Runx2 ubiquitination axis controlling VSMC calcification. |
SMC-specific PTEN knockout mice (Cre/LoxP), siRNA knockdown, in vitro calcification assay, Runx2 ubiquitination assay, ex vivo arterial calcification |
Arteriosclerosis, thrombosis, and vascular biology |
Medium |
25378413
|
| 2015 |
FOXO1 directly regulates CCR7 and ICAM-1 promoters (shown by ChIP and promoter reporter assays) in dendritic cells; FOXO1 nuclear localization is induced by bacteria via the MAPK pathway; lineage-specific FOXO1 deletion impairs DC phagocytosis, chemotaxis, and lymph node homing, which can be rescued by ICAM-1 and CCR7 re-expression. |
ChIP, promoter reporter assay, lineage-specific knockout (CD11c.Cre), rescue with plasmid transfection, in vivo lymph node homing assay |
Journal of immunology |
High |
25786691
|
| 2015 |
FOXO1 enhances keratinocyte migration and wound healing by upregulating TGFβ1 under normal glucose conditions; under high glucose, FOXO1 nuclear localization is induced but FOXO1 does not bind the TGFβ1 promoter—instead it drives SERPINB2 and CCL20 expression that inhibits migration; insulin treatment or FOXO1 silencing rescues impaired migration in high glucose. |
Lineage-specific Foxo1 deletion, FOXO1 promoter binding analysis, siRNA, high-glucose cell culture, wound healing migration assay |
The Journal of cell biology |
High |
25918228
|
| 2016 |
FOXO1 suppresses MYC signaling in endothelial cells to restrain glycolysis and mitochondrial respiration, acting as a gatekeeper of endothelial quiescence; endothelial-restricted FOXO1 deletion causes increased EC proliferation and vessel hyperplasia, while forced FOXO1 expression restricts vascular expansion; restoration of MYC in FOXO1-overexpressing endothelium normalizes metabolism and branching. |
Endothelial-specific knockout and overexpression mouse models, metabolic flux assays (glycolysis, respiration), MYC rescue experiments, EC proliferation assays |
Nature |
High |
26735015
|
| 2017 |
DDB1-CUL4A E3 ubiquitin ligase promotes FOXO1-driven hepatic gluconeogenesis by degrading CRY1 (a known DDB1 target); loss of Ddb1 in hepatocytes downregulates FOXO1 protein and impairs gluconeogenic response; CRY1 depletion increases nuclear FOXO1 abundance and enhances gluconeogenesis, linking circadian clock protein degradation to FOXO1 stability. |
Hepatocyte-specific Ddb1 knockout mice, Cry1 depletion in vivo, FOXO1 protein stability analysis, gluconeogenic gene expression, glucose production assay |
Diabetes |
Medium |
28790135
|
| 2017 |
SCP4 (CTDSPL2) is a nuclear phosphatase that directly dephosphorylates FoxO1/3a, promoting nuclear retention and transcriptional activation of PEPCK1 and G6PC gluconeogenic genes; SCP4 overexpression increases hepatic glucose production; SCP4 gene ablation causes neonatal hypoglycemia. |
In vitro dephosphorylation assay (SCP4 on FoxO1/3a), ectopic expression, siRNA knockdown, SCP4 knockout mice (neonatal hypoglycemia), glucose production assay |
Diabetes |
High |
28851713
|
| 2018 |
FOXO1 directly regulates VEGFA expression in keratinocytes (shown by in vitro promoter assay); keratinocyte-specific FOXO1 deletion reduces VEGFA expression in wounds, resulting in reduced endothelial cell proliferation, reduced angiogenesis, and impaired wound re-epithelialization. |
Keratinocyte-specific Foxo1 knockout mice, VEGFA promoter reporter assay, endothelial proliferation assay, porcine wound model with FOXO1 inhibitor |
The Journal of pathology |
High |
29574902
|
| 2018 |
Foxo1 directly binds the Il9 and Irf4 promoters in Th9 cells (shown by ChIP and luciferase assays) to transactivate them; pharmacological or genetic disruption of Foxo1 in CD4+ T cells reduces IL-9 and promotes IL-17A/IFNγ; adoptive transfer of Foxo1-inhibitor-treated Th9 cells reduces asthma-like symptoms. |
ChIP, luciferase promoter assay, Foxo1 pharmacological inhibitor (AS1842856), CD4-specific Foxo1 knockout, adoptive transfer airway allergy model |
Scientific reports |
Medium |
29339772
|
| 2019 |
Glucagon suppresses hepatic mitochondrial complex III and IV activity and reduces mitochondrial biogenesis (NRF1, TFAM, MFN2 expression) in a FOXO1-dependent manner; hepatocyte-specific Foxo1 deletion largely rescues glucagon-induced mitochondrial dysfunction, establishing FOXO1 as a mediator of glucagon's effects on mitochondrial function. |
Foxo1 hepatocyte-specific knockout mice, glucagon treatment, mitochondrial function assays (complex activity), db/db diabetic mice |
The Journal of endocrinology |
Medium |
31026811
|
| 2020 |
METTL14 promotes FOXO1 expression in endothelial cells by directly binding FOXO1 mRNA, increasing its m6A modification, and enhancing translation through YTHDF1 recognition; METTL14 also interacts with FOXO1 protein and together they act on VCAM-1 and ICAM-1 promoters to promote inflammatory gene transcription. |
Methylated RNA immunoprecipitation (RIP) sequencing, RIP assay, co-immunoprecipitation, ChIP, METTL14 knockout mice, TNF-α inflammation model |
Theranostics |
Medium |
32802173
|
| 2020 |
FOXO1 binds directly to the KLF5 promoter in cardiomyocytes to increase KLF5 expression; KLF5 in turn binds the NOX4 promoter to induce NOX4 expression, reactive oxygen species, and ceramide accumulation, causing diabetic cardiomyopathy; cardiomyocyte-specific FOXO1 deletion protects from diabetic cardiomyopathy by reducing KLF5. |
ChIP (FOXO1 on KLF5 promoter; KLF5 on NOX4 promoter), cardiomyocyte-specific FOXO1 knockout mice, AAV-mediated KLF5 delivery, pharmacological KLF5 inhibition, oxidative stress and ceramide measurements |
Circulation research |
High |
33539225
|
| 2020 |
S100A11 interacts with HDAC6 to inhibit HDAC6 deacetylase activity, thereby releasing FOXO1 from HDAC6 binding and increasing FOXO1 acetylation; acetylated FOXO1 activates autophagy and lipogenesis programs promoting liver steatosis. |
Co-immunoprecipitation (S100A11-HDAC6 interaction), HDAC6 inhibitor, FOXO1 inhibitor, adenoviral overexpression, in vivo high-fat diet model, lipid staining |
Cellular and molecular gastroenterology and hepatology |
Medium |
33075563
|
| 2021 |
Akt phosphorylation of FoxO1 is required for Sox10 expression in oligodendrocytes; unphosphorylated (nuclear) FoxO1 represses the Sox10 promoter; Akt-triple-knockout oligodendrocyte lineage mice lack mature oligodendrocytes and myelination with downregulated Sox10, identifying a FoxO1 phosphorylation-dependent mechanism for oligodendrocyte differentiation. |
OL lineage-specific Akt1/2/3 triple conditional knockout mice, Sox10 promoter reporter assay, FoxO1 phosphorylation-site mutants, ChIP (FoxO1 on Sox10 promoter) |
The Journal of neuroscience |
Medium |
34385359
|
| 2021 |
Foxo1 in intestinal epithelial cells regulates goblet cell autophagy and mucus secretion; IEC-specific Foxo1 deletion impairs goblet cell autophagy and mucus secretion, leading to gut microbiota dysbiosis, disrupted tight junction organization, and increased susceptibility to intestinal inflammation. |
Intestinal epithelial cell-specific Foxo1 conditional knockout mice, goblet cell autophagy assays, microbiome analysis, tight junction protein analysis, colitis susceptibility assay |
The Journal of experimental medicine |
Medium |
34287641
|
| 2022 |
FoxO1 in hepatic macrophages (Kupffer cells) promotes pro-inflammatory M1 polarization by counteracting Stat6 signaling; myeloid-specific FoxO1 knockout skews macrophage polarization from M1 to M2 and reduces hepatic inflammation, steatosis, and fibrosis in NASH. |
Myeloid-specific FoxO1 conditional knockout (LysM-Cre), M1/M2 polarization markers, Stat6 pathway analysis, NASH diet model, high-fat diet model |
The Journal of clinical investigation |
High |
35700043
|
| 2023 |
FOXO1 directly binds the promoter regions of CD36 and STEAP4 genes in bovine adipocytes (shown by ChIP and site-directed mutagenesis) and regulates their transcriptional activity, linking FOXO1 to lipogenesis through the AMPK and PI3K/AKT pathways. |
ChIP, site-directed mutagenesis of FOXO1 binding sites, transcriptomic and metabolomics analyses, siRNA knockdown |
International journal of biological macromolecules |
Medium |
37506793
|