Correction: Corrigendum: Serine is a natural ligand and allosteric activator of pyruvate kinase M2

Nature 491, 458–462 (2012); doi:10.1038/nature11540 In Fig. 1a of this Letter, the western blot originally published in the PKM2 panel was a re-probe of the blot used in the PKM1 panel and the signal picked up was from the first antibody (PKM1) and not from PKM2. We have repeated the experiment on three different membranes with the antibodies used in the original paper for PKM1, PKM2 and total PKM, using actin as the loading control (Fig.