Utrophin

Utrophin is a is_associated_with::protein that in humans is encoded by the UTRN is_associated_with::gene.

The protein encoded by this gene is a component of the is_associated_with::cytoskeleton. Utrophin was found during research into is_associated_with::Duchenne's muscular dystrophy. The name is a contraction for ubiquitous is_associated_with::dystrophin. The 900 kb is_associated_with::gene for utrophin is found on the long arm of is_associated_with::human is_associated_with::chromosome 6. Utrophin was discovered due to its homology with is_associated_with::dystrophin. It was found by screening a is_associated_with::peptide containing the is_associated_with::C-terminal domain of is_associated_with::dystrophin against is_associated_with::cDNA libraries. The homology varies over its full length from less than 30% in regions of the central rod structural domain, to 85% (identity 73%) for the is_associated_with::actin binding domain.

The is_associated_with::tertiary structure of utrophin contains a C-terminus that consists of protein–protein interaction motifs that interact with is_associated_with::dystroglycan, a central rod region consisting of a triple coiled-coil repeat, and an is_associated_with::actin-binding N-terminus.

In normal is_associated_with::muscle cells, utrophin is located at the neuromuscular synapse and myotendinous junctions. It is necessary for normal membrane maintenance, and for the clustering of the is_associated_with::acetylcholine receptor. In adult humans, utrophin is_associated_with::RNA is found ubiquitously, as the name implies, being abundant in the is_associated_with::brain,  is_associated_with::kidney, is_associated_with::liver, is_associated_with::lung, is_associated_with::muscle, is_associated_with::spleen and is_associated_with::stomach. In the human is_associated_with::fetus during muscle differentiation, utrophin is found at the is_associated_with::sarcolemma. It disappears when the fetus begins to express is_associated_with::dystrophin.

Utrophin expression is dramatically increased in patients with Duchenne's muscular dystrophy (and female carriers), both in those is_associated_with::muscle fibers lacking is_associated_with::dystrophin and in rare, revertant fibers that express dystrophin.

No reports have yet associated mutation in the utrophin gene with disease, but it does not seem to play a critical role in development, since mice without utrophin develop normally.