Tag: RING ligases

TRIM5α is a specialised antiviral ubiquitin ligase that recognises retroviral capsids, assembles K63‑linked ubiquitin chains and promotes autophagic degradation. Its tripartite motif and SPRY domain enable potent restriction of retroviruses, making TRIM5α a key factor in innate antiviral immunity and retroviral defence.

TRIM21 is a unique intracellular antibody receptor and RING finger ubiquitin ligase that neutralises antibody‑coated viruses inside the cytosol. Through its PRY/SPRY domain and tripartite motif, TRIM21 triggers rapid ubiquitin‑mediated degradation and activates antiviral signalling pathways. Its roles in immunity, autoimmunity and biotechnology make TRIM21 a key regulator of intracellular defence.

TRIM25 is a RING finger ubiquitin ligase that activates the antiviral sensor RIG‑I through K63‑linked ubiquitination. Its tripartite motif and PRY/SPRY domain enable precise regulation of innate immune signalling, interferon production and viral restriction. TRIM25 is targeted by multiple viruses, highlighting its importance as a frontline antiviral factor.

The TRIM family is a large group of single‑chain RING finger ubiquitin ligases that regulate innate immunity, antiviral defence, autophagy, transcription and protein quality control. Defined by their tripartite motif—RING, B‑box and coiled‑coil domains—TRIM proteins use diverse C‑terminal regions to achieve precise substrate specificity. Their roles in immunity, development and cancer make them key regulators of cellular homeostasis.

Cbl‑c is an epithelial‑specific RING finger ubiquitin ligase that regulates EGFR and other receptor tyrosine kinases through targeted ubiquitination. With a streamlined domain architecture and restricted expression pattern, Cbl‑c maintains epithelial homeostasis and prevents excessive RTK signalling. Loss or mutation of Cbl‑c contributes to epithelial cancers, highlighting its importance in growth control and oncogenesis.

Cbl‑b is a single‑chain RING finger ubiquitin ligase that acts as a master regulator of immune activation. By ubiquitinating key signalling molecules in T‑cells, B‑cells and NK cells, Cbl‑b maintains immune tolerance and prevents hyperactivation. Loss of Cbl‑b leads to autoimmunity and enhanced anti‑tumour immunity, making it a critical player in immune homeostasis and a promising target in cancer immunotherapy.

The CBL family of ubiquitin ligases—c‑Cbl, Cbl‑b and Cbl‑c—are single‑chain RING finger E3 enzymes that regulate receptor tyrosine kinase signalling, immune activation and epithelial homeostasis. Through their TKB and RING domains, CBL proteins control ubiquitination, endocytosis and signal attenuation. Dysregulation of CBL ligases contributes to cancer, autoimmunity and inflammatory disorders, highlighting their importance in cellular regulation and disease.

Single‑chain RING finger ubiquitin ligases form an important subgroup of E3 enzymes within the ubiquitin–proteasome system. Unlike multi‑subunit Cullin–RING ligases,…

RING finger ubiquitin ligases are the largest class of E3 enzymes in the ubiquitin–proteasome system, defined by a zinc‑binding cross‑brace RING domain that positions E2~Ub for direct ubiquitin transfer. They regulate essential cellular processes including cell cycle progression, DNA repair, immunity, and neuronal function. Dysregulation of RING and RBR ligases such as MDM2 and Parkin contributes to cancer and neurodegeneration, while modern PROTAC therapeutics harness CRL4^CRBN and CRL2^VHL complexes to redirect ubiquitination toward disease‑associated proteins.