Protein from skin tissues and cultured cells were extracted for Western blotting as described (Ai et al., 2007 (link)). Primary antibodies were rabbit anti-mouse KLF4 (1:1000, GenSpin,), rabbit anti-mouse CXCR4 (1:1000, eBioscience) and rat anti-mouse β-actin (1:1000, Sigma-Aldrich).