Characterization of Primary Cilia and Intraflagellar Transport 20 in the Epidermis

This study investigated the role of primary cilia and Intraflagellar Transport 20 (Ift20) in epidermal development, homeostasis, and wound healing using transgenic mouse models. It was found that both the Interfollicular Epidermis (IFE) and hair follicles (HFs) were highly ciliated throughout development and in adult skin. The targeted ablation of Ift20 in hair follicle stem cells (HF-SCs) inhibited ciliogenesis and hair regrowth, indicating that Ift20 was crucial for maintaining HF-SC identity and proper hair follicle function. Loss of Ift20 led to changes in HF-SC marker expression and ectopic differentiation. Additionally, Ift20 was shown to regulate keratinocyte migration during wound healing in a primary cilia-independent manner by mediating focal adhesion integrin recycling through a Rab5-dependent mechanism. Overall, Ift20 played a critical role in maintaining HF-SC identity and facilitating keratinocyte migration.