Hair follicle formation after birth is critically regulated by epidermal laminin γ1 Mice with epidermal deletion of laminin γ1 display retarded hair follicle morphogenesis Hair growth defects correlate with reduced hair matrix cell proliferation and disturbed hair shaft differentiation Modulation of the BMP-MSX2-HOXC13-FOXN1 signaling axis by laminin γ1 contributes to proper hair shaft differentiation