[5][6] Alternatively spliced transcript variants for this gene have been described but the full-length nature of only one has been determined.

[7] TRIM21 is part of the RoSSA ribonucleoprotein, which includes a single polypeptide and one of four small RNA molecules.

[6] RoSSA interacts with autoantigens in patients with Sjögren's syndrome and systemic lupus erythematosus.

[6] In addition, the inability for lupus-prone macrophages to degrade immune complexes in the lysosome results in the leakage of autoantibodies into the cytosol that can bind to TRIM21 and enhance NF-κB signaling.

In this assay, TRIM21 and antibodies are delivered into cells through electroporation, and the targeted protein is degraded within a few minutes.