Module 12: Figure MLP−/− Ca2+ responses

Reduced Ca2+ responses in muscle-specific LIM protein (MLP)−/− mice.

A. Ca2+ responses in muscle-specific LIM protein (MLP)−/− mice (MLPKO) had a much reduced Ca2+ transient, which was restored to normal if phospholamban was also removed. In the double knockout (DKO), the rate of recovery was increased. B. The statistics reveal that there was no change in the diastolic Ca2+ level, but there was a marked reduction in the Ca2+ content of the sarcoplasmic reticulum (SR). When phospholamban was removed, the Ca2+ content of the store was increased above that of the wild-type (WT), and this increased availability of Ca2+ was able to compensate for the effect of removing MLP. Reproduced from Cell, Vol. 99, Minamisawa, S., Hoshijima, M., Chu, G., Ward, C.A., Frank, K., Gu, Y., Martone, M.E., Wang, Y., Ross, J., Kranias, E.G., Giles, W.R. and Chien, K.R., Chronic phospholamban-sarcoplasmic reticulum calcium ATPase interaction is the critical calcium cycling defect in dilated cardiomyopathy, pp. 313–322. Copyright (1999), with permission from Elsevier; see Minamisawa et al. 1999.