B-Raf and C-Raf Are Required for Melanocyte Stem Cell Self-Maintenance

The study found that B-Raf and C-Raf kinases were essential for the self-maintenance of melanocyte stem cells (MSCs) in mice, as their absence led to hair graying due to MSC depletion in hair follicles. While these kinases were not necessary for early melanocyte development, they were crucial for MSC cell-cycle entry and maintenance. The research also revealed a separation between SCF/Kit and Raf/ERK signaling pathways, with B-Raf and C-Raf being functionally redundant, as single knockouts did not result in hair graying. Various genetic models and techniques were used to demonstrate these findings.