• Product name
  • Description
    Goat polyclonal to TRIM21/SS-A
  • Host species
  • Tested applications
    Suitable for: IHC-P, ICC/IF, Flow Cyt, WBmore details
  • Species reactivity
    Reacts with: Human
  • Immunogen

    Synthetic peptide corresponding to TRIM21/SS-A aa 463-475 (N terminal).


    (Peptide available as ab23028)

  • Positive control
    • WB: HEK293 lysate overexpressing human TRIM21/SS-A. IHC-P: Human colon tissue. ICC/IF: U2OS cells. Flow Cyt: HeLa cells.
  • General notes

    Previously labelled as TRIM21



Our Abpromise guarantee covers the use of ab4369 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
IHC-P Use at an assay dependent concentration.
ICC/IF Use a concentration of 10 µg/ml.
Flow Cyt Use a concentration of 10 µg/ml.
WB Use a concentration of 0.2 - 1 µg/ml. Can be blocked with Human TRIM21/SS-A peptide (ab23028).

In transfected HEK293 transiently expressing full-length Human TRIM21/SS-A (myc and DYKDDDDK tagged), a band of approx. 60kDa was observed. No bands were observed in mock-transfected HEK293 and the same band was observed using anti-myc tag antibody


  • Function
    E3 ubiquitin-protein ligase whose activity is dependent on E2 enzymes, UBE2D1, UBE2D2, UBE2E1 and UBE2E2. Forms a ubiquitin ligase complex in cooperation with the E2 UBE2D2 that is used not only for the ubiquitination of USP4 and IKBKB but also for its self-ubiquitination. Component of cullin-RING-based SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes such as SCF(SKP2)-like complexes. A TRIM21-containing SCF(SKP2)-like complex is shown to mediate ubiquitination of CDKN1B ('Thr-187' phosphorylated-form), thereby promoting its degradation by the proteasome. Monoubiquitinates IKBKB that will negatively regulates Tax-induced NF-kappa-B signaling. Negatively regulates IFN-beta production post-pathogen recognition by polyubiquitin-mediated degradation of IRF3. Mediates the ubiquitin-mediated proteasomal degradation of IgG1 heavy chain, which is linked to the VCP-mediated ER-associated degradation (ERAD) pathway. Promotes IRF8 ubiquitination, which enhanced the ability of IRF8 to stimulate cytokine genes transcription in macrophages. Plays a role in the regulation of the cell cycle progression. Enhances the decapping activity of DCP2. Exists as a ribonucleoprotein particle present in all mammalian cells studied and composed of a single polypeptide and one of four small RNA molecules. At least two isoforms are present in nucleated and red blood cells, and tissue specific differences in RO/SSA proteins have been identified. The common feature of these proteins is their ability to bind HY RNAs.2.
  • Tissue specificity
    Isoforms 1 and 2 are expressed in fetal and adult heart and fetal lung.
  • Pathway
    Protein modification; protein ubiquitination.
  • Sequence similarities
    Belongs to the TRIM/RBCC family.
    Contains 1 B box-type zinc finger.
    Contains 1 B30.2/SPRY domain.
    Contains 1 RING-type zinc finger.
  • Domain
    The coiled-coil is necessary for the cytoplasmic localization. The B30.2/SPRY domain is necessary for the cytoplasmic localization, the interaction with IRF3 and for the IRF3-driven interferon beta promoter activity. The RING-type zinc finger is necessary for ubiquitination and for the IRF3-driven interferon beta promoter activity. Interacts with SKP2 and CUL1 in a RING finger-independent manner.
  • Post-translational
    Autoubiquitinated; does not lead to its proteasomal degradation. Deubiquitinated by USP4; leading to its stabilization.
  • Cellular localization
    Cytoplasm. Nucleus. Cytoplasm > P-body. Enters the nucleus upon exposure to nitric oxide. Localizes to small dot- or rod-like structures in the cytoplasm, called cytoplasmic bodies (P-body) that are located underneath the plasma membrane and also diffusely in the cytoplasm and are highly motil in cells. Cytoplasmic bodies are located along the microtubules and do not share the same cytoplasmic bodies with TRIM5. Colocalizes with DCP2 in P-body.
  • Information by UniProt
  • Database links
  • Alternative names
    • 52 kDa ribonucleoprotein autoantigen Ro/SS-A antibody
    • 52 kDa Ro protein antibody
    • 52kD Ro/SSA autoantigen antibody
    • Autoantigen Ro/SSA, 52-KD antibody
    • E3 ubiquitin-protein ligase TRIM21 antibody
    • RING finger protein 81 antibody
    • RNF81 antibody
    • Ro 52 antibody
    • Ro(SS-A) antibody
    • Ro52 antibody
    • RO52_HUMAN antibody
    • Sicca syndrome antigen A antibody
    • Sjoegren syndrome type A antigen antibody
    • Sjogren syndrome antigen A1 antibody
    • Sjogren syndrome type A antigen antibody
    • SS-A antibody
    • SSA antibody
    • SSA1: Sjogren syndrome antigen A1 (52kDa ribonucleoprotein autoantigen SS-A/Ro) antibody
    • TRIM21 antibody
    • Tripartite motif protein TRIM21 antibody
    • Tripartite motif-containing 21 antibody
    • Tripartite motif-containing protein 21 antibody
    see all


  • Lanes 1-2 : Anti-TRIM21/SS-A antibody (ab4369) at 1 µg/ml
    Lane 3 : Anti-Myc tag antibody at 1/1000 dilution

    Lanes 1 & 3 : HEK293 lysate overexpressing Myc-tagged SSA1 (in RIPA buffer)
    Lane 2 : Control HEK293 lysate (in RIPA buffer)

    Lysates/proteins at 10 µg per lane.

    Observed band size: 55 kDa
    why is the actual band size different from the predicted?
    Additional bands at: 48 kDa. We are unsure as to the identity of these extra bands.

    Primary incubation for 1 hour. Detected using chemiluminescence.

  • Immunocytochemistry/Immunofluorescence analysis of U2OS cells labelling TRIM21/SS-A with ab4369 at 10 µg/ml. Cells were paraformaldehyde fixed and permeabilized with 0.15% triton. Primary antibody icubation was for 1 hour followed by incubation with an Alexa Fluor® 488-conjugated secondary antibody at 2 µg/ml. DAPI nuclear counterstain was used.

    Negative control: Unimmunized goat IgG (10 µg/ml) followed by an Alexa Fluor® 488-conjugated secondary antibody (2 µg/ml).

  • Flow cytometry analysis of HeLa cells labelling TRIM21/SS-A with ab4369 (blue line) at 10 µg/ml. Cells were fixed with paraformaldehyde and permeabilized with 0.5% Triton. Incubated with the primary antibody for 1 hour followed by incubation with Alexa Fluor® 488-conjugated secondary antibody at 1 µg/ml.

    IgG control: Unimmunized goat IgG (black line) followed by Alexa Fluor® 488-conjugated secondary antibody.


This product has been referenced in:
  • Kuboshima M  et al. Presence of serum tripartite motif-containing 21 antibodies in patients with esophageal squamous cell carcinoma. Cancer Sci 97:380-6 (2006). Read more (PubMed: 16630135) »
See 1 Publication for this product

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