State-Dependent Signaling by Cav1.2 Regulates Hair Follicle Stem Cell Function

The study explored the role of the voltage-gated calcium channel Ca_v1.2 in hair follicle stem cell function, particularly in the context of Timothy syndrome (TS), which is associated with baldness. Although hair follicle stem cells express Ca_v1.2, they do not exhibit voltage-dependent calcium currents. The TS mutation in Ca_v1.2 acted in a dominant-negative manner, significantly delaying the anagen phase of hair growth. Conversely, L-type channel blockers induced anagen and counteracted the TS phenotype by acting through Ca_v1.2. The channel regulated the production of the BMP inhibitor follistatin-like1 (Fstl1) from the bulge, which in turn influenced stem cell quiescence. These findings highlighted the role of Ca_v1.2 in nonexcitable tissues and suggested potential therapeutic targets for tissue regeneration.