Product Info

ELISA 1:10000, WB 1:500-1:2000, IF/ICC 1:100-1:500, IHC 1:50-1:200
*The optimal dilutions should be determined by the end user.

WB: For western blot detection of denatured protein samples. IHC: For immunohistochemical detection of paraffin sections (IHC-p) or frozen sections (IHC-f) of tissue samples. IF/ICC: For immunofluorescence detection of cell samples. ELISA(peptide): For ELISA detection of antigenic peptide.

Monoclonal [AFB1799]
FOXP3 antibody detects endogenous levels of total FOXP3.
Cite Format: Affinity Biosciences Cat# BF0630, RRID:AB_2833823.
Mouse IgG1 in phosphate buffered saline (without Mg2+ and Ca2+), pH 7.4, 150mM NaCl, 0.02% sodium azide and 50% glycerol. Store at -20 °C. Stable for 12 months from date of receipt.


AIID; DIETER; Forkhead box P3; Forkhead box protein P3; FOXP3; FOXP3_HUMAN; FOXP3delta7; Immune dysregulation polyendocrinopathy enteropathy X linked; Immunodeficiency polyendocrinopathy enteropathy X linked; IPEX; JM2; MGC141961; MGC141963; OTTHUMP00000025832; OTTHUMP00000025833; OTTHUMP00000226737; PIDX; Scurfin; XPID;



Purified recombinant fragment of human FOXP3 expressed in E. Coli.

FOXP3 (a 431 amino acid protein) is a member of the forkhead/winged-helix family of transcriptional regulators and is highly conserved across mammals. FOXP3 is essential for normal immune homeostasis. FOXP3 is stably and constitutively expressed at a high level in CD25 + CD4 positive regulatory T cells, at low level in CD4 positive/CD25 negative cells, and is absent in CD4 negative/CD8 positive T cells. FOXP3 may be a master regulatory gene and a more specific marker of regulatory T cells than other T cells.

PTMs - Q9BZS1 As Substrate

Site PTM Type Enzyme
S25 Phosphorylation
K31 Acetylation
S33 Phosphorylation
T44 Phosphorylation
T115 Phosphorylation
T138 Phosphorylation
S142 Phosphorylation
K179 Acetylation
K227 Acetylation
K250 Acetylation
K252 Acetylation
K263 Acetylation
K268 Acetylation
S270 Phosphorylation
S274 Phosphorylation
S275 Phosphorylation
Y342 Phosphorylation P06239 (LCK)
K356 Ubiquitination
K393 Ubiquitination
S418 Phosphorylation
S422 Phosphorylation P11309 (PIM1)

Research Backgrounds


Transcriptional regulator which is crucial for the development and inhibitory function of regulatory T-cells (Treg). Plays an essential role in maintaining homeostasis of the immune system by allowing the acquisition of full suppressive function and stability of the Treg lineage, and by directly modulating the expansion and function of conventional T-cells. Can act either as a transcriptional repressor or a transcriptional activator depending on its interactions with other transcription factors, histone acetylases and deacetylases. The suppressive activity of Treg involves the coordinate activation of many genes, including CTLA4 and TNFRSF18 by FOXP3 along with repression of genes encoding cytokines such as interleukin-2 (IL2) and interferon-gamma (IFNG). Inhibits cytokine production and T-cell effector function by repressing the activity of two key transcription factors, RELA and NFATC2. Mediates transcriptional repression of IL2 via its association with histone acetylase KAT5 and histone deacetylase HDAC7. Can activate the expression of TNFRSF18, IL2RA and CTLA4 and repress the expression of IL2 and IFNG via its association with transcription factor RUNX1. Inhibits the differentiation of IL17 producing helper T-cells (Th17) by antagonizing RORC function, leading to down-regulation of IL17 expression, favoring Treg development. Inhibits the transcriptional activator activity of RORA. Can repress the expression of IL2 and IFNG via its association with transcription factor IKZF4 (By similarity).


Polyubiquitinated, leading to its proteasomal degradation in regulatory T-cells (Treg) which is mediated by STUB1 in a HSPA1A/B-dependent manner. Deubiquitinated by USP7 leading to increase in protein stability.

Phosphorylation at Ser-418 regulates its transcriptional repressor activity and consequently, regulatory T-cells (Treg) suppressive function. Dephosphorylated at Ser-418 by protein phosphatase 1 (PP1) in Treg cells derived from patients with rheumatoid arthritis. Phosphorylation by CDK2 negatively regulates its transcriptional activity and protein stability (By similarity).

Acetylation on lysine residues stabilizes FOXP3 and promotes differentiation of T-cells into induced regulatory T-cells (iTregs) associated with suppressive functions. Deacetylated by SIRT1.

Undergoes proteolytic cleavage in activated regulatory T-cells (Treg), and can be cleaved at either the N- or C-terminal site, or at both sites.

Subcellular Location:

Nucleus. Cytoplasm.
Note: Predominantly expressed in the cytoplasm in activated conventional T-cells whereas predominantly expressed in the nucleus in regulatory T-cells (Treg). The 41 kDa form derived by proteolytic processing is found exclusively in the chromatin fraction of activated Treg cells (By similarity).

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionSubcellular location
Subunit Structure:

Homodimer. Dimerization is essential for its transcriptional regulator activity. Interacts with IKZF3. Isoform 1 (via LXXLL motif), but not isoform 2, interacts with isoform 4 of RORA (via AF-2 motif). Interacts with STUB1, HSPA8 and HSPA1A/B. Interacts with PPP1CA, PPP1CB and PPP1CG. Interacts with KAT5 and HDAC7. Interacts with HDAC9 in the absence of T-cell stimulation. Interacts with USP7. Interacts with isoform 2 of ZFP90 and can form a complex with TRIM28 in the presence of isoform 2 of ZFP90. Interacts with RUNX1. Interacts with RORC. Interacts with RELA and NFATC2. Interacts with RUNX2, RUNX3 and IKZF4 (By similarity).


The fork-head DNA-binding domain is essential for its dimerization and interaction with NFATC2.

Research Fields

· Human Diseases > Immune diseases > Inflammatory bowel disease (IBD).

· Organismal Systems > Immune system > Th17 cell differentiation.   (View pathway)

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