The Transmembrane Protein LRIG1 Regulates Receptor Tyrosine Kinases in Skin Development and Homeostasis

The study investigated the role of the transmembrane protein LRIG1 in regulating receptor tyrosine kinases (RTKs) during skin development and homeostasis, particularly focusing on its impact on the hair cycle. Using a transgenic mouse model with skin-specific overexpression of LRIG1, researchers found that these mice developed alopecia from 3 months of age, with a thicker epidermis and the presence of utricles. The study revealed that LRIG1 influenced RTKs differently at various hair cycle stages, with reduced phosphorylation of EGFR during the first catagen and anagen phases, and lower IGF1R expression during first catagen and telogen. The severity of alopecia increased when LRIG1 transgenic mice were crossed with a line expressing a dominant negative EGFR, indicating that hair loss was primarily EGFR-dependent. These findings highlighted LRIG1's significant role in epidermal regulation through RTKs in a hair cycle-dependent manner.