Myotilin

Myotilin is a protein that in humans is encoded by the MYOT gene. Myotilin (myofibrillar titin-like protein) also known as TTID (TiTin Immunoglobulin Domain) is a muscle protein that is found within the Z-disc of sarcomeres.

== Structure == Myotilin is a 55.3 kDa protein composed of 496 amino acids. Myotilin was originally identified as a novel alpha-actinin binding partner with two Ig-like domains, that localized to the Z-disc. The I-type Ig-like domains reside at the C-terminal half, and are most homologous to Ig domains 2-3 of palladin and Ig domains 4-5 of myopalladin and more distantly related to Z-disc Ig domains 7 and 8 of titin. The C-terminal region hosts the binding sites for Z-band proteins, and 2 Ig domains are the site of homodimerization for myotilin. By contrast, the N-terminal part of myotilin is unique, consisting of a serine-rich region with no homology to known proteins. Several disease-associated mutations involve serine residues within the serine-rich domain. Myotilin expression in human tissues is mainly restricted to striated muscles and nerves. In muscles, myotilin is predominantly found within the Z-discs. Myotilin forms homodimers and binds alpha-actinin, actin, Filamin C, FATZ-1, FATZ-2 and ZASP.