Fig. 4

Sarcomeric binding sites of chaperones relative to I-band titin epitopes. (a) Nearest epitope-to-mid-Z-disc distance of gold particles indicating the position of sarcomere-bound HSP27, αB-crystallin (αBC) and HSP90, in comparison to that of the T12, N2A and PEVK titin epitopes, on immunoelectron micrographs of CTRL, LGMD2A, and MFM-filaminopathy (‘FLN-C’) myofibers at different sarcomere lengths. N = 30 sarcomeres analyzed per antibody and group. Lines are linear regression. (b) Schematic on top shows the domain architecture of I-band titin (N2A isoform) and the positions of anti-titin antibodies used (T12, N2A, PEVK). Immunoelectron micrographs below were taken from CTRL and diseased human skeletal muscle biopsy samples labeled with anti-titin T12, N2A and PEVK antibodies, respectively. Z, Z-disc region