Function
Obscurin (Obs) or KIAA1556 is a giant sarcomeric signalling protein expressed in striated muscles. Other giant proteins in the family include titin and nebulin. It is a multidomain protein containing adhesion modules and signaling domains. These domains include: 68 Ig domains, 2 fibronectin domains, 1 calcium/calmodulin-binding domain, 1 RhoGEF domain with PH domain and 2 serine/thereonine kinase domains.
Obscurin binds small ankyrin 1 which is part of the sarcoplasmic reticulum membrane. It associates with the contractile apparatus via binding to titin and sarcomeric myosin. Obscurin is assumed to play a key role in modulating the organization and assembly of sarcomeric reticulum and the myofibril[1].
For more details see Group:MUZIC:Obscurin.
Disease
Mutations of Obs are found in hypertrophy cardiomyopathy[2].
