PKC and PKN in heart disease

Fig. 1. Schematic overview of the PKC and PKN families of kinases. Evolutionary analysis of human PKN and PKC kinase domains. Domain layout of conventional, novel and atypical PKCs, as well as PKN isozymes is shown, in addition to ligands, agonists or binding partners for their activation. Abbreviations: DAG – diacylglycerol; FA – fatty acid; HR1 – polybasic coiled-coil homology region 1; PB1 – Phox and Bem1; PIP2 – phosphatidylinositol 4,5-bisphosphate; PS – phosphatidylserine; Rho - Ras homology.

Fig. 2. Activation of PKCs and PKNs. A-B. Schematic steps for the canonical activation of prototypical conventional PKC isozymes (A) or PKNs (B) are illustrated. C. Non-canonical activation by protease activity or tyrosine phosphorylation.

Fig. 3. Phospholamban phosphorylation at Ser10. A. Verification of the specificity of the phospholamban (PLN) Ser10 antibody using in vitro kinase assay-mediated phosphorylation of wildtype (wt) or Ser10Ala mutant (S10A) GST-PLN fusion proteins. Only phosphorylation at Ser10, but not S10A mutant PLN is recognized by the antibody. B. Analysis of SERCA2, total and phospho-Ser10 PLN levels in total cardiac extracts of control (Ctl), Ankrd1 knockout (Ankrd1-ko), MLP knockout (MLP-ko) or Ankrd1/MLP double knockout (dKO) mice indicates increased monomeric PLN phosphorylation at Ser10 in MLP-ko. Cardiac actin was used as loading control. C. Analysis of SERCA2, total and phospho-Ser10 PLN levels in cardiac extracts from non-failing individuals and dilated cardiomyopathy patients. Molecular weights of monomeric and pentameric phospholamban species are indicated, and reveal increased monomeric phosphorylation of PLN at Ser10 in patients with pathologically decreased SERCA2 levels. GAPDH was used as loading control.