Supplementary Figure 1: Validation of key reagents and assays.

a, top, IHC with antibody recognizing specifically Ldha (same as used in Fig. 1a). bottom, IHC with antibody recognizing multiple isoforms of Ldh protein. Scale bars indicate 20 micrometers. b, the sorting strategy employed to isolate two populations of cells from the bulge. This particular sort was used to isolate the protein samples shown by western blot in Fig. 1b. c, Validation of colorimetric Ldh enzyme activity assay. The highest Ldh enzyme activity was observed in HFSC bulge and in the muscle. Activity indicated by purple stain; pink color is nuclear fast red counterstain. In absence of substrate lactate there was no detectable activity (purple stain). Right, Additional validation of colorimetric Ldh enzyme activity assay. Enzyme activity inhibited by treating skin with HCl before addition of staining solution with substrate lactate. No Ldh activity (purple stain) detected. Skin in which enzyme activity is not inhibited by Hydrochloric Acid (HCl) shows highest Ldh enzyme activity in HFSC bulge and in the muscle. Scale bars indicate 50 micrometers.