Recombinant Midline 1 (MID1)

The protein encoded by this gene is a member of the tripartite motif (TRIM) family, also known as the 'RING-B box-coiled coil' (RBCC) subgroup of RING finger proteins. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. This protein forms homodimers which associate with microtubules in the cytoplasm. The protein is likely involved in the formation of multiprotein structures acting as anchor points to microtubules. Mutations in this gene have been associated with the X-linked form of Opitz syndrome, which is characterized by midline abnormalities such as cleft lip, laryngeal cleft, heart defects, hypospadias, and agenesis of the corpus callosum. This gene was also the first example of a gene subject to X inactivation in human while escaping it in mouse. Multiple different transcript variants are generated by alternate splicing; however, the full-length nature of some of the variants has not been determined. [provided by RefSeq, Jul 2010]

MID1: Has E3 ubiquitin ligase activity towards IGBP1, promoting its monoubiquitination, which results in deprotection of the catalytic subunit of protein phosphatase PP2A, and its subsequent degradation by polyubiquitination. Defects in MID1 are the cause of Opitz GBBB syndrome 1 (OGS1). A congenital midline malformation syndrome 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. MID1 mutations produce proteins with a decreased affinity for microtubules. Belongs to the TRIM/RBCC family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Ligase; Cytoskeletal; Ubiquitin ligase; EC 6.3.2.19; EC 6.3.2.-; Ubiquitin conjugating system

Chromosomal Location of Human Ortholog: Xp22

Cellular Component: microtubule; microtubule associated complex; cytoplasmic microtubule; spindle; cytosol

Molecular Function: protein homodimerization activity; zinc ion binding; protein heterodimerization activity; microtubule binding; ubiquitin protein ligase binding; phosphoprotein binding; ligase activity

Biological Process: negative regulation of microtubule depolymerization; metabolic process; cytokine and chemokine mediated signaling pathway; microtubule cytoskeleton organization and biogenesis; pattern specification process; positive regulation of stress-activated MAPK cascade

Disease: Tracheoesophageal Fistula With Or Without Esophageal Atresia; Opitz Gbbb Syndrome, X-linked