Figure 4.

Cellular Validation and Myomesin Isoform Specificity

(A) Close up of the OL3:My4L interface. OL3 is shown as surface representation and colored according to its electrostatic potential. The myomesin L linker interacting with OL3 is shown as stick representation.

(B) Quantification of endogenous obscurin displaced in neonatal rat cardiomyocytes expressing GFP-fused wild-type My4LMy5 (n = 11) and its T622V (n = 10), T622K (n = 9), I625T (n = 10), V627Y (n = 13) variants. Amino acid replacements in the L linker inspired by myomesin-2 (T622K and V627Y) and myomesin-3 (I625T) sequences abrogate competition. Error bars are SEM values. ^∗∗∗p ≤ 0.001.

(C) Example of the competitive effect of overexpressed GFP-fused My4LMy5 (WT) on endogenous obscurin in NRCs. The separate channels for endogenous myomesin, GFP, endogenous obscurin, as well as the combined and ratiometric images with overlaid GFP mask for the outline of the transfected cell are shown. The false-color scale range indicator shows an increased obscurin/myomesin ratio. The scale bar represents 10 μm.

(D–G) Similar to (C) for overexpressed GFP-fused My4LMy5 T622V (D), T622K (E), I625T (F), and V627Y (G). The scale bar represents 10 μm.