Picture from Forbes JG et al. (2010) J Mol Biol "Extensive and modular intrinsically disordered segments in C. elegans TTN-1 and ...."
Fig. 3. Immunofluorescence localization of TTN-1 in the sarcomere. Each panel of three (a-c, d-f, etc.) confocal images shows results of co-staining adult body wall muscle with the indicated pairs of antibodies. (a-c) Anti-TTN-1 C-terminus antibody EU143 localizes both between dense bodies and outside of dense bodies in the I-band. Both MHC B and twitchin had been shown previously to localize to the A-band except for the middle of the A-band. Note that co-staining of EU143 with either MHC B (a-c) or with twitchin (g-i) shows some overlap at the outer edge of the A-band (yellow in c and i). (j-l) Antibody 9/10 localizes in the same region as the EU143 antibody. (m) Drawing of a portion of body wall muscle indicating the organization of the myofilament lattice and antibody staining in this obliquely striated muscle. The drawing is oriented such that the edge on view of the obliquely striated I-band and A-band stacks have the same orientation as in the immunofluorescence images. Dense bodies are analogous to Z-disks in mammalian cross striated muscle. (n) Proposed model of TTN-1 orientation, maximal span and variable environment in the sarcomere. The TTN-1 molecules span from the dense bodies toward the A-band in an N-to-C orientation, with some reaching as far as the edge of the thick filaments. Such molecules are misregistered across the sarcomere (bottom three filaments), due to the tapered shape of the dense body. The molecules are also offset significantly between adjacent sarcomeres due to the lateral offset of the sarcomeres in this obliquely striated muscle (top two filaments). The scale bar represents 5 um.