Insulin-like growth factor binding protein-3 (IGFBP-3) localizes to and modulates proliferative epidermal keratinocytes in vivo

Abstract

Background: The colocalization of insulin-like growth factor binding protein-3 (IGFBP-3) and IGF-I receptor (IGF-IR) in the basal/germinative layer of the epidermis suggests a key role in modulating epidermal homeostasis. Objectives: We aimed to clarify both the specific cellular localization and the effect of excess epidermal IGFBP-3 on keratinocyte proliferation. Methods: (i) Total RNA was isolated from fluorescence-activated cell sorted basal human keratinocyte subtypes [keratinocyte stem cells, transit amplifying keratinocytes (TA), postmitotic differentiating keratinocytes (PMD)], and real-time polymerase chain reaction analysis was used to determine the abundance of IGFBP-3 and IGF-IR ..