What is TRIM21 Protein

The TRIM21 protein (Tripartite Motif Containing 21), also known as Ro52, is part of the TRIM family of proteins. These proteins are recognized for their triple motif structure consisting of a RING finger domain, one or two B-box domains, and a coiled-coil domain. An essential member of the ubiquitin-proteasome system (UPS), the TRIM21 protein has been studied extensively for its scientific relevance, disease correlation, and potential applications in biomedicine.

The TRIM21 protein was discovered during the mid-1980s by researchers who were investigating autoimmune diseases, particularly Sjögren's syndrome and systemic lupus erythematosus (SLE). They noticed that certain patients had autoantibodies against a 52-kDa protein, later identified as TRIM21.

Gene Locus and Protein Structure

The human gene that encodes the TRIM21 protein is located on locus 11p15.5. It contains 7 exons and spans more than 14 kilobases. The TRIM21 protein itself boasts a characteristic structure of three motifs: a RING domain at the N-terminal, B-box domains in the middle, and a coiled-coil domain alongside a PRY/SPRY domain at the C-terminal.

TRIM21 Function

TRIM21 exhibits several important functions. It plays a crucial role in immune regulation due to its E3 ubiquitin ligase activity that helps regulate innate immune signaling. It can also capture invading viruses in the cytoplasm by binding to the Fc region of antibodies. After capturing the virus, TRIM21 uses its ligase activity to mediate the ubiquitination and degradation of the invading pathogen. In addition to its immune functions, it is involved in apoptosis and cell cycle regulation.

Fig1. Mechanism of TRIM21 mediated anti-viral function (Foss, S., et al. 2019)

TRIM21-related Signal Pathway

TRIM21 has been implicated in several signaling pathways, wherein it modulates protein stability and transcriptional activity. The most prominent include interferon (IFN) and nuclear factor kappa B (NF-κB) signaling pathways. By acting as an E3 ubiquitin-protein ligase, TRIM21 can modulate the turnover of several substrates involved in these pathways, influencing inflammatory and immune responses.

TRIM21-Related Diseases

Mutations or aberrant expressions of TRIM21 have been linked to numerous diseases, particularly autoimmune and inflammatory disorders. For example, elevated levels of TRIM21 antibodies are present in patients with Sjögren's syndrome, SLE, rheumatoid arthritis, and myositis. Additionally, polymorphisms in the TRIM21 gene have been associated with increased susceptibility to these diseases. Recent studies also suggest a potential role for TRIM21 in cancer, neurological disorders, and viral infections.

TRIM21 Protein's Applications in Biomedicine

The immunological and biological significance of TRIM21 has paved the way for its applications in biomedicine. Its ability to recognize, bind to, and degrade antibody-coated viruses suggest its potential as an antiviral therapy. It might also be manipulated to modulate immune responses, potentially treating autoimmune and inflammatory diseases. Moreover, targeting TRIM21 could prevent or reduce the aggressive growth of certain types of cancer.

In conclusion, the TRIM21 protein plays a vital role in the immune response regulation, viral infections, cell cycle, and apoptosis. Its links to various diseases make it a promising target for therapeutic interventions. Continuous research and clinical trials are required to fully understand the potential of TRIM21 protein and its mechanistic pathways. The more we learn about this protein, the closer we become to breakthroughs in disease treatment and prevention.

Our Featured Products

Cat.No.	Product Name	Species	Source (Host)	Tag
TRIM21-5540H	Recombinant Human TRIM21 protein, His-tagged	Human	Yeast	His
TRIM21-0259H	Recombinant Human TRIM21 Protein, Tag Free	Human	Confidential	Tag Free
TRIM21-3037H	Recombinant Human TRIM21 protein, His-tagged	Human	E.coli	His
TRIM21-537HF	Recombinant Full Length Human TRIM21 Protein, GST-tagged	Human	In Vitro Cell Free System	GST
Trim21-6646M	Recombinant Mouse Trim21 Protein, Myc/DDK-tagged	Mouse	HEK293T	Myc/DDK
Trim21-4539M	Recombinant Mouse Trim21 protein, His-SUMO-tagged	Mouse	E.coli	His-SUMO
TRIM21-4768R	Recombinant Rhesus Macaque TRIM21 Protein, His (Fc)-Avi-tagged	Rhesus Macaque	HEK293	His (Fc)-Avi

Reference

• Foss, S., Bottermann, M., Jonsson, A., Sandlie, I., James, L. C., & Andersen, J. T. (2019). TRIM21—From Intracellular Immunity to Therapy. Frontiers in Immunology, 10, 474156. https://doi.org/10.3389/fimmu.2019.02049