Obscurin, a giant sarcomeric Rho guanine nucleotide exchange factor protein involved in sarcomere assembly.

ABSTRACT: Vertebrate-striated muscle is assumed to owe its remarkable order to the molecular ruler functions of the giant modular signaling proteins, titin and nebulin. It was believed that these two proteins represented unique results of protein evolution in vertebrate muscle. In this paper we report the identification of a third giant protein from vertebrate muscle, obscurin, encoded on chromosome 1q42. Obscurin is approximately 800 kD and is expressed specifically in skeletal and cardiac muscle. The complete cDNA sequence of obscurin reveals a modular architecture, consisting of >67 intracellular immunoglobulin (Ig)- or fibronectin-3-like domains with multiple splice variants. A large region of obscurin shows a modular architecture of tandem Ig domains reminiscent of the elastic region of titin.

SUBMITTER: Young P 

PROVIDER: S-EPMC2196875 | biostudies-literature | 2001 Jul

REPOSITORIES: biostudies-literature