• Product name

  • Description

    Rabbit polyclonal to STAT1
  • Host species

  • Specificity

    ab31369 detects endogenous levels of STAT1 protein around Tyrosine 701.
  • Tested applications

    Suitable for: WB, ELISA, IHC-Pmore details
  • Species reactivity

    Reacts with: Mouse, Rat, Human
  • Immunogen

    Synthetic peptide corresponding to Human STAT1 aa 668-717.
    Database link: P42224

  • Positive control

    • IHC: breast carcinoma WB: COLO205 cells extract



Our Abpromise guarantee covers the use of ab31369 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
WB 1/500 - 1/1000. Detects a band of approximately 87 kDa (predicted molecular weight: 87 kDa).
ELISA 1/10000.
IHC-P Use at an assay dependent concentration.


  • Function

    Signal transducer and activator of transcription that mediates signaling by interferons (IFNs). Following type I IFN (IFN-alpha and IFN-beta) binding to cell surface receptors, Jak kinases (TYK2 and JAK1) are activated, leading to tyrosine phosphorylation of STAT1 and STAT2. The phosphorylated STATs dimerize, associate with ISGF3G/IRF-9 to form a complex termed ISGF3 transcription factor, that enters the nucleus. ISGF3 binds to the IFN stimulated response element (ISRE) to activate the transcription of interferon stimulated genes, which drive the cell in an antiviral state. In response to type II IFN (IFN-gamma), STAT1 is tyrosine- and serine-phosphorylated. It then forms a homodimer termed IFN-gamma-activated factor (GAF), migrates into the nucleus and binds to the IFN gamma activated sequence (GAS) to drive the expression of the target genes, inducing a cellular antiviral state.
  • Involvement in disease

    Note=STAT1 deficiency results in impaired immune response leading to severe mycobacterial and viral diseases. In the case of complete deficiency, patients can die of viral disease.
    Defects in STAT1 are a cause of mendelian susceptibility to mycobacterial disease (MSMD) [MIM:209950]; also known as familial disseminated atypical mycobacterial infection. This rare condition confers predisposition to illness caused by moderately virulent mycobacterial species, such as Bacillus Calmette-Guerin (BCG) vaccine and environmental non-tuberculous mycobacteria, and by the more virulent Mycobacterium tuberculosis. Other microorganisms rarely cause severe clinical disease in individuals with susceptibility to mycobacterial infections, with the exception of Salmonella which infects less than 50% of these individuals. The pathogenic mechanism underlying MSMD is the impairment of interferon-gamma mediated immunity whose severity determines the clinical outcome. Some patients die of overwhelming mycobacterial disease with lepromatous-like lesions in early childhood, whereas others develop, later in life, disseminated but curable infections with tuberculoid granulomas. MSMD is a genetically heterogeneous disease with autosomal recessive, autosomal dominant or X-linked inheritance.
  • Sequence similarities

    Belongs to the transcription factor STAT family.
    Contains 1 SH2 domain.
  • Post-translational

    Phosphorylated on tyrosine and serine residues in response to IFN-alpha, IFN-gamma, PDGF and EGF. Phosphorylation on Tyr-701 (lacking in beta form) by JAK promotes dimerization and subsequent translocation to the nucleus. Phosphorylation on Ser-727 by several kinases including MAPK14, ERK1/2 and CAMKII on IFN-gamma stimulation, regulates STAT1 transcriptional activity. Phosphorylation on Ser-727 promotes sumoylation though increasing interaction with PIAS. Phosphorylation on Ser-727 by PKCdelta induces apoptosis in response to DNA-damaging agents.
    Sumoylated by SUMO1, SUMO2 and SUMO3. Sumoylation is enhanced by IFN-gamma-induced phosphorylation on Ser-727, and by interaction with PIAS proteins. Enhances the transactivation activity.
  • Cellular localization

    Cytoplasm. Nucleus. Translocated into the nucleus in response to IFN-gamma-induced tyrosine phosphorylation and dimerization.
  • Information by UniProt
  • Database links

  • Alternative names

    • Signal transducer and activator of transcription 1 91kD antibody
    • CANDF7 antibody
    • DKFZp686B04100 antibody
    • IMD31A antibody
    • IMD31B antibody
    • IMD31C antibody
    • ISGF 3 antibody
    • ISGF-3 antibody
    • OTTHUMP00000163552 antibody
    • OTTHUMP00000165046 antibody
    • OTTHUMP00000165047 antibody
    • OTTHUMP00000205845 antibody
    • Signal transducer and activator of transcription 1 91kDa antibody
    • Signal transducer and activator of transcription 1 antibody
    • Signal transducer and activator of transcription 1, 91kD antibody
    • Signal transducer and activator of transcription 1-alpha/beta antibody
    • STAT 1 antibody
    • Stat1 antibody
    • STAT1_HUMAN antibody
    • STAT91 antibody
    • Transcription factor ISGF 3 components p91 p84 antibody
    • Transcription factor ISGF-3 components p91/p84 antibody
    • Transcription factor ISGF3 components p91/p84 antibody
    • XStat1 antibody
    see all


  • All lanes : Anti-STAT1 antibody (ab31369) at 1/1000 dilution

    Lane 1 : COLO205 cells extract
    Lane 2 : COLO205 cells extract with synthetic phosphopeptide

    Predicted band size: 87 kDa
    Observed band size: 87 kDa

  • Immunohistochemical analysis of paraffin-embedded breast carcinoma. Left: Using STAT1 antibody(ab31369, diluted 1:100); Right: The same antibody preincubated with synthesized peptide.


This product has been referenced in:

  • Jiang L  et al. The Pros1/Tyro3 axis protects against periodontitis by modulating STAT/SOCS signalling. J Cell Mol Med 23:2769-2781 (2019). Read more (PubMed: 30729671) »
  • Ma X  et al. Alendronate promotes osteoblast differentiation and bone formation in ovariectomy-induced osteoporosis through interferon-ß/signal transducer and activator of transcription 1 pathway. Exp Ther Med 15:182-190 (2018). Read more (PubMed: 29375681) »
See all 17 Publications for this product

Customer reviews and Q&As

1-4 of 4 Abreviews or Q&A


Thank you for your patience.

The antibody ab31369 detects both alpha and beta forms of STAT1 when it is not phosphorylated at Y701. We believe that your treatment is increasing the expression of total STAT1 as well as the phosphorylated form.

Ab30645 detects the phosphorylation of Y701 whether or not the protein is phosphorylated at S727.

Please let me know if you need any additional information or assistance.

Read More


Thank you for your emails and for your patience while I've looked into these questions.

I've heard back from the lab regarding the specificity of ab31369. The antibody should detect both the alpha and beta forms, thoughwe haven't specifically tested whether it reacts with the phosphorylated protein too. There might be some reactivity with the phosphoprotein, but we would expect it to be weaker than reactivity with the non-phosphorylated protein. Based on our conversation last week and the images you sent, it looks like the antibody is reacting quite strongly with the phosphoprotein. The lab might be running some tests to determine this, and I'll keep you posted on anything else that we find out. I'll also need to check whether the antibody could detect STAT1 cleaved at residue 694, as I don't have the full immunogen seequence in my notes.

Ab30645 is specific for STAT1 phosphorylated at Y701, and I would expect it to react with protein phosphorylated at both Y701 and S727. Some phospho-specific antibodies show weak cross-reactivity for other phospho-proteins, so it is possible that ab30645 would weakly cross-react with protein only phosphorylated at S727. I'm not sure that this has been specifically tested by the lab, but I'll check with them and get back to shortly with that information.

Regarding the images, based on molecular weights I would expect the higher band to be the alpha isoform phosphorylated at both Y701 and S727, while the lower bands would be either the beta isoform (phosphorylated or not) or alpha isoform only phosphorylated at Y701. Phosphorylations eachtend to add some weight to the protein. I think further studies might need to be done in order to know this for sure, but that seems to be the most likely explanation. There are too many possible post-translational statesat similar molecular weights in order to know for sure what each band represents based on band size.

For ab11909, I may not be understanding the question as intended, but the full-length inactive ATF6 protein is cleaved by proteases during ER stress, so I would expect this form of the protein if the cells are under this type of stress. The full-length ATF6 most likely isn't completely lost, butthe cleaved form could certainly be more abundant in the sample and the inactive ATF6 at undetectable levels. It is also possible for proteases in the samples to cleave the protein during protein isolation/sample preparation but this would generally result in several lower molecular weight bands on the Western blot. If the samples are not treated with enough protease inhibitors (or the right mix of protease inhibitors) or were not kept on ice during preparation, it is possible for this to occur. If the samples were treated correctly, and the cells were under ER stress, than I expectthat specific proteases just cleaved the protein to yield the active form. Please let me know if I misunderstood the question or if there is more information that you're seeking.

I hope this information will be useful, but please let me know if you have further questions or if there is anything else that we can do for you. I'll be back in touch once I have more information from the lab about the STAT1 antibodies.

Read More


Thank you for calling Abcam earlier today.

I am sorry about the problems you have been having with ab31369 in western blotting. The antibody is covered under our Abpromise for six months and is guaranteed to work in western blot on human samples (both tissue and cell lysate). Since you are seeing no signal with this antibody, then I would be very happy to send a replacement. A few possible alternatives are:


If you can please provide me with the Abcam order number for ab31369, and also let me know which antibody you would like to receive as a replacement, I will be happy to have it sent to you as soon as possible.

Please let me know if there is anything else I can help you with.

Read More


I am sorry that this antibody did not perform as stated on the datasheet. If payment has already been made on the original order and you wish to receive a refund, please ask your purchasing department to contact our accounting department so that we may gather the correct information needed for the refund. To avoid confusion, please ensure your accounts department is aware of how the credit note is being used. Our accounting department can be contacted by email at us.credits@abcam.com or by telephone using the information at the Contact Us link in the top right corner of our website. Please refer to the credit note ID in any correspondence with our accounting department. The credit note ID is for your reference only and does not automatically guarantee the credit. I hope this experience will not prevent you from purchasing other products from us in the future. Our Scientific Support team is always at your service, should you require further expert advice.  

Read More

For licensing inquiries, please contact partnerships@abcam.com

Sign up