Fig. 8. Schematic drawing of the N2B and is2 regions of titin and their associated proteins. DRAL/FHL-2 interacts directly with the N2B and is2 regions and serves as an adaptor molecule to couple the metabolic enzymes MM-CK, adenylate kinase and phosphofructokinase to titin. In addition, MM-CK may be bound to the M-band region of the sarcomere via its association with additional M-band proteins (not shown here). The domain nomenclature and amino acid numbering correspond to that of the human cardiac titin sequence [X90568 (Labeit and Kolmerer, 1995)].