Midline-1 (Tripartite motif-containing protein 18, Putative transcription factor XPRF, RING finger protein 59) is a 667 amino acid protein encoded by the human gene MID1. Midline-1 belongs to the TRIM/RBCC family and contains two B box-type zinc fingers, one B30.2/SPRY domain, one COS domain, one fibronectin type-III domain and one RING-type zinc finger. Midline-1 is believed to have E3 ubiquitin ligase activity which targets the catalytic subunit of protein phosphatase 2 for degradation. It is a cytoplasmic protein found as a homodimer or heterodimer with Midline-2. It also interacts with IGBP1 (Lymphocyte signaling protein A4). Defects in MID1 are the cause of Opitz syndrome type I (OS-I). OS-I is an X-linked recessive disorder characterized by hypertelorism, genital-urinary defects such as hypospadias in males and splayed labia in females, lip-palate-laryngotracheal clefts, imperforate anus, developmental delay and congenital heart defects.
E3 ubiquitin-protein ligase Midline-1; Finger on X and Y (in rat only on X); FXY; MID1; Midin; midline 1 (Opitz/BBB syndrome); midline 1 RING finger protein; midline-1; Opitz/BBB syndrome; Putative transcription factor XPRF; RING finger protein 59; RING finger protein Midline-1; RING-type E3 ubiquitin transferase Midline-1; RNF59; TRIM18; tripartite motif protein TRIM18; Tripartite motif-containing protein 18; XPRF; zinc finger on X and Y, mouse, homolog of