Telethonin is a 167-residue protein which complexes with the large muscle protein, titin. The very N-terminus of titin, composed of two immunoglobulin-like (Ig) domains, referred to as Z1 and Z2, interacts with the N-terminal region (residues 1-53) of telethonin, mediating the antiparallel assembly of two Z1Z2 domains. The C-terminus of the telethonin appears to induce dimerisation of this 2:1 titin/telethonin structure which thus forms a complex necessary for myofibril assembly and maintenance of the intact Z-disk of skeletal and cardiac muscles [1].

1: Evidence for a dimeric assembly of two titin/telethonin complexes induced by the telethonin C-terminus. Pinotsis N, Petoukhov M, Lange S, Svergun D, Zou P, Gautel M, Wilmanns M; J Struct Biol. 2006;155:239-250. PMID:16713295