(A) Representative myocyte micrograph used to determine myocyte area/volume ratios. 25 × LWD lens. (B) Myocyte surface areas (Cm) are significantly increased in DHHC5-GT myocytes vs matched WT myocytes. (C) Myocyte volumes are not significantly different in DHHC5-GT myocytes from 4 to 6 week old mice. (D) Myocyte surface area/volume ratios are increased by 27% in DHHC5-GT myocytes. (E) Cardiac tissue Cm, monitored via NIC recording, is increased by 21% in right ventricular strips from DHHC5-GT mice (n = 5) vs control litter mates (n = 5). (F) Na/K pump current densities are increased by 32% in DHHC5-GT myocytes. (G) An average 17% increase of NCX1 current density is not significant. (H) Amine PEGylation assay to determine the surface membrane fractions of PLM and NCX1 in WT and DHHC5-GT hearts. Western blot density profiles are shown for three hearts, one control heart that was not PEGylated (gray), one WT heart (black) and one DHHC5-GT heart (red). PLM, actin and NCX1 are blotted, and the PEGylated PLM and NCX1 densities (i.e., protein resident in the cell surface) are shifted 5 kD from control densities. (I) Fractions of PLM and NCX1 that can be PEGylated, and therefore reside in the sarcolemma, are increased by 27 and 23%, respectively, in DHHC5-GT hearts. For both WT and DHHC5-GT hearts, n = 3. For all data from myocytes, n >40 using myocytes from three animals.