PLN and hydrops fetalis: Using phospho-specific antibodies we also examined the phosphorylation status of PLN (Fig. 6B) and observed that whilst the phosphorylation status of the PKA-dependent residue (Ser-16) was unaltered in HF, there was increased phosphorylation at the adjacent Ca2 +-calmodulin kinase II- (CAMKII) dependent Thr-17 residue (to 221 ± 73% of control, P < 0.05); an effect most likely due to the 320 ± 40% increase (relative to control) in CAMKII expression in HF (Fig. 6C, P < 0.001).