Fig 2. Disturbed Ca²⁺ handling and Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) activation by Doxorubicin (Dox) treatment.

Neonatal rat cardiomyocytes were treated with 1μM Dox or medium as control for the indicated time. (A) Timeframe of (monomeric) phospholamban phosphorylation at the CaMKII specific phosphorylation site Thr17 (p-PLN (Thr17); n = 4) and autophosphorylation of CamKII at Thr286 (p-CaMKII (Thr286); n = 3) after 0-48h Dox treatment. Phosphorylated protein was normalized for total expression of respective protein. (B) H₂O₂-levels in the cell culture supernatant (n = 3). RLU values were divided by relative cell number. (C) SR Ca²⁺ content in control and Dox treated cells after 0-24h. Amplitude and diastolic Ca²⁺ levels determined from Ca²⁺ transients after Dox or medium administration for 0-24h (n = 3). *p < 0.05 for 1-way ANOVA with Bonferroni post hoc testing.