Tripartite motif-containing protein 55 (TRIM55)

Tripartite motif-containing protein 55 (TRIM55) is a muscle-specific E3 ubiquitin ligase belonging to the tripartite motif-containing (TRIM) protein family, characterized by a RING zinc finger domain that mediates protein-protein interactions[1][3][7]. TRIM55 is essential for sarcomere assembly in skeletal muscle where it transiently interacts with microtubules, myosin, and titin[1][7]. Beyond muscle biology, TRIM55 regulates key processes in cancer, cardiovascular disease, and immune response. It acts as an E3 ubiquitin ligase, targeting substrates such as c-Myc, NF90, and p100 for proteasomal degradation, thereby influencing pathways like cell proliferation, migration, and noncanonical NF-κB signaling[2][3][5]. TRIM55 is downregulated in several cancers (hepatocellular carcinoma, colorectal cancer), where its loss is associated with poor prognosis and increased metastatic potential; conversely, it can act as an oncogene in gastric cancer. In the immune system, TRIM55 is required for B cell maturation, germinal center formation, and antibody production, making it a potential therapeutic target for autoimmune diseases such as lupus[5]. Variants in TRIM55 are also linked to heart failure, underlining its role in cardiovascular health[1][3]. **Note:** No approved therapeutics are currently known to target TRIM55 directly. It is viewed as an emerging target in research for oncology, cardiology, and immunology applications[1][3][5].

Other names

MURF-2RNF29MuRF2muscle-specific RING finger protein 2ring finger protein 29

Modulation of substrate ubiquitination, leading to proteasomal degradation (e.g., c-Myc, NF90, p100); Regulation of signaling pathways including HIF1α/VEGF, TGFβ/Smad, and noncanonical NF-κB