Module 12: Figure Ca2+ in triadin-1-overexpressing mice
Cardiac hypertrophy in triadin 1-overexpressing mice.
Triadin 1 is located within the sarcoplasmic reticulum (SR) and associates with the type 2 ryanodine receptor (RYR2), junctin and calsequestrin (CSQ). In the triadin 1 (TRD)-overexpressing mouse, there was a large increase in the protein level of triadin 1, with a compensatory decrease in the levels of RYR2 and junctin. The major change with regard to the Ca2+ transient was a considerable prolongation of the Ca2+ transient in the triadin 1−/− mouse (blue dotted trace) compared with the wild-type (WT) (red trace). When integrated over time, the average intracellular Ca2+ level will be higher in the triadin 1-overexpressing myocytes, and this may be the signal that results in hypertrophy. Reproduced from Kirchhefer, U., Neumann, J., Baba, H.A., Begrow, F., Kobayashi, Y.M., Reinke, Y., Schmitz, W. and Jones, L.R. (2001) Cardiac hypertrophy and impaired relaxation in transgenic mice overexpressing triadin 1. J. Biol. Chem. 276:4142–4149, with permission from the American Society for Biochemistry and Molecular Biology; see Kirchhefer et al. 2001.