E3 ubiquitin-protein ligase midline-1 (MID1)

E3 ubiquitin-protein ligase midline-1 (MID1) is a cytoplasmic, microtubule-associated enzyme belonging to the tripartite motif-containing (TRIM) family, specifically subgroup C-I. MID1 contains a RING finger domain (conferring E3 ubiquitin ligase activity), multiple zinc finger domains, a coiled-coil region, a COS domain, a fibronectin type III (FN3) repeat, and a B30.2 (PRY-SPRY) domain. MID1 orchestrates targeted protein degradation and turnover by tagging substrates (e.g., the catalytic subunit of protein phosphatase 2A, PP2Ac) with ubiquitin, influencing processes including cytoskeleton organization, cell division, cell migration, and signal transduction. It is essential for midline developmental patterning and its dysfunction is causative for the X-linked form of Opitz G/BBB syndrome, a congenital disorder with diverse midline developmental defects. MID1 also impacts translational regulation in polyglutamine repeat disorders and modulates key signaling cascades including mTOR and Sonic Hedgehog (SHH) pathways; it is expressed widely, especially during embryogenesis, and participates in inflammatory and possibly oncogenic processes[1][2][3][4].

Other names

Tripartite motif-containing protein 18TRIM18RING finger protein 59RNF59FXYMidinPutative transcription factor XPRFzinc finger on X and Y (ZNFXY)Opitz/BBB syndrome proteinBBBG1GBBBGBBB1MIDINOGS1OSOSXXPRFmidline 1 RING finger proteintripartite motif protein TRIM18

Inhibition or modulation of E3 ubiquitin ligase activity (theoretical; no clinical agents directly validated for MID1 modulation). Modulation of downstream pathways such as mTOR, PP2A, and Hedgehog signaling.