Functional analysis of α-Parvin in vivo

The focal adhesion (FA) protein α-Parvin (αPv) has been shown to regulate integrin signalingand integrin-actin linkage. Here we report that the conditional deletion of the αPv gene inkeratinocytes leads to impaired hair follicle (HF) morphogenesis, epidermal hyperplasia andmicro-blistering. Expression of integrin α6 was reduced on αPv-deficient keratinocytes,leading to defects in hemidesmosome (HD) formation and integrin-dependent adhesionassociated with rupture of the basement membrane and the presence of proliferatingkeratinocytes in suprabasal layers of the epidermis. Suprabasal expression of integrins wasaccompanied by disturbed and delayed terminal differentiation of αPv-deficientkeratinocytes. The defects in FA formation/maturation and actin cytoskeleton organizationresulted in impaired migration of primary αPv-deficient keratinocytes which is likely thecause for the impaired HF morphogenesis and cycling and progressive loss of hair. Our datademonstrate that αPv is required for epidermal homeostasis and HF development byfacilitating integrin signaling and actin cytoskeleton organization in keratinocytes.