Fig. 2

Titin isoform expression and phosphorylation in normal and diseased myofibers. (a) Representative SDS-polyacrylamide gels (left panel) to monitor titin molecular size (N2A isoform) and the titin:myosin heavy chain (MHC) expression ratio in normal (CTRL), LGMD2A, and MFM-filaminopathy (‘FLN-C’) muscles (Vastus lateralis). Right panel shows mean titin sizes and mean titin:MHC ratios. (b) Typical Western blots of titin bands on loose SDS-polyacrylamide gels (left panel) using phosphosite-specific antibodies to phospho-serines P-S11878 and P-S12022 in the PEVK domain of titin and to all phospho-serines/−threonines in titin (P-S/T). “PVDF” is the (transiently) coomassie-stained blotting membrane, the signal from which is shown in lieu of a loading control (not available in the titin size range). Right panel shows mean phosphorylation levels for CTRL, LGMD2A and MFM-filaminopathy muscles. Data are means ± SEM (n = 3/group); *p < 0.05, **p < 0.01, in Bonferroni-adjusted t-test