Protein O-mannosyl-transferase 1 is an enzyme that in humans is encoded by the POMT1 gene. [4] [5] It is a member of the dolichyl-phosphate-mannose-protein mannosyltransferases.
O-mannosylation is an important protein modification in eukaryotes that is initiated by an evolutionarily conserved family of protein O-mannosyltransferases. POMT1 shares sequence similarity with protein O-mannosyltransferases of S. cerevisiae. In yeast, these enzymes are located in the endoplasmic reticulum (ER) and are required for cell integrity and cell wall rigidity. POMT1 also shows similarity to the Drosophila 'rotated abdomen' (rt) gene, which when mutated causes defects in myogenesis and muscle structure.[supplied by OMIM] [5]
It is associated with limb-girdle muscular dystrophy type LGMD2K. [6]
In the retina it is known that O-mannosylation of α-DG carried out by POMT1 is crucial for the establishment of proper synapses at the outer plexiform layer and the transmission of visual information from cones and rods to their postsynaptic neurons, i.e. bipolar and horizontal cells. [7] Lack of POMT1 expression results in a good number of impairments in photoreceptors that have been documented at the proteomic, morphological and physiological levels. [7] [8]
A congenital disorder of glycosylation is one of several rare inborn errors of metabolism in which glycosylation of a variety of tissue proteins and/or lipids is deficient or defective. Congenital disorders of glycosylation are sometimes known as CDG syndromes. They often cause serious, sometimes fatal, malfunction of several different organ systems in affected infants. The most common sub-type is PMM2-CDG where the genetic defect leads to the loss of phosphomannomutase 2 (PMM2), the enzyme responsible for the conversion of mannose-6-phosphate into mannose-1-phosphate.
Limb–girdle muscular dystrophy or (LGMD) is a genetically and clinically heterogeneous group of rare muscular dystrophies. It is characterised by progressive muscle wasting which affects predominantly hip and shoulder muscles. LGMD has an autosomal pattern of inheritance and currently has no known cure or treatment.
Dystrophin is a rod-shaped cytoplasmic protein, and a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane. This complex is variously known as the costamere or the dystrophin-associated protein complex (DAPC). Many muscle proteins, such as α-dystrobrevin, syncoilin, synemin, sarcoglycan, dystroglycan, and sarcospan, colocalize with dystrophin at the costamere.
Walker–Warburg syndrome (WWS), also called Warburg syndrome, Chemke syndrome, HARD syndrome, Pagon syndrome, cerebroocular dysgenesis (COD) or cerebroocular dysplasia-muscular dystrophy syndrome (COD-MD), is a rare form of autosomal recessive congenital muscular dystrophy. It is associated with brain and eye abnormalities. This condition has a worldwide distribution. The overall incidence is unknown but a survey in North-eastern Italy has reported an incidence rate of 1.2 per 100,000 live births. It is the most severe form of congenital muscular dystrophy with most children dying before the age of three years.
Dysferlin also known as dystrophy-associated fer-1-like protein is a protein that in humans is encoded by the DYSF gene.
The autoimmune regulator (AIRE) is a protein that in humans is encoded by the AIRE gene. It is a 13kb gene on chromosome 21q22.3 that has 545 amino acids. AIRE is a transcription factor expressed in the medulla of the thymus. It is part of the mechanism which eliminates self-reactive T cells that would cause autoimmune disease. It exposes T cells to normal, healthy proteins from all parts of the body, and T cells that react to those proteins are destroyed.
Laminopathies are a group of rare genetic disorders caused by mutations in genes encoding proteins of the nuclear lamina. They are included in the more generic term nuclear envelopathies that was coined in 2000 for diseases associated with defects of the nuclear envelope. Since the first reports of laminopathies in the late 1990s, increased research efforts have started to uncover the vital role of nuclear envelope proteins in cell and tissue integrity in animals.
The photoreceptor cell-specific nuclear receptor (PNR), also known as NR2E3, is a protein that in humans is encoded by the NR2E3 gene. PNR is a member of the nuclear receptor super family of intracellular transcription factors.
Fukutin is a eukaryotic protein necessary for the maintenance of muscle integrity, cortical histogenesis, and normal ocular development. Mutations in the fukutin gene have been shown to result in Fukuyama congenital muscular dystrophy (FCMD) characterised by brain malformation - one of the most common autosomal-recessive disorders in Japan. In humans this protein is encoded by the FCMD gene, located on chromosome 9q31. Human fukutin exhibits a length of 461 amino acids and a predicted molecular mass of 53.7 kDa.
Cone-rod homeobox protein is a protein that in humans is encoded by the CRX gene.
Delta-sarcoglycan is a protein that in humans is encoded by the SGCD gene.
Myotilin is a protein that in humans is encoded by the MYOT gene. Myotilin also known as TTID is a muscle protein that is found within the Z-disc of sarcomeres.
Cyclic nucleotide-gated cation channel alpha-3 is a protein that in humans is encoded by the CNGA3 gene.
Protein O-linked-mannose beta-1,2-N-acetylglucosaminyltransferase 1 is an enzyme that in humans is encoded by the POMGNT1 gene.
The human gene UBR1 encodes the enzyme ubiquitin-protein ligase E3 component n-recognin 1.
Protein O-mannosyl-transferase 2 is an enzyme that in humans is encoded by the POMT2 gene.
Chitobiosyldiphosphodolichol beta-mannosyltransferase is an enzyme that is encoded by ALG1 whose structure and function has been conserved from lower to higher organisms.
Anoctamin 5 (ANO5) is a protein that in humans is encoded by the ANO5 gene.
Muscle–eye–brain (MEB) disease, also known as muscular dystrophy-dystroglycanopathy congenital with brain and eye anomalies A3 (MDDGA3), is a kind of rare congenital muscular dystrophy (CMD), largely characterized by hypotonia at birth. Patients suffer from muscular dystrophy, central nervous system abnormalities and ocular abnormalities, the condition is degenerative.