Life before and beyond blistering: The role of collagen XVII XVII in epidermal physiology

摘要

Abstract Type XVII collagen ( COL 17) is a transmembranous protein that is mainly expressed in the epidermal basal keratinocytes. Epidermal‐dermal attachment requires COL 17 expression at the hemidesmosomes of the epidermal basement membrane zone because congenital COL 17 deficiency leads to junctional epidermolysis bullosa and acquired autoimmunity to COL 17 induces bullous pemphigoid. Recently, in addition to facilitating epidermal‐dermal attachment, COL 17 has been reported to serve as a niche for hair follicle stem cells, to regulate proliferation in the interfollicular epidermis and to be present along the non‐hemidesmosomal plasma membrane of epidermal basal keratinocytes. This review focuses on the physiological properties of COL 17 in the epidermis, its role in maintaining stem cells and its association with signalling pathways. We propose possible solutions to unanswered questions in this field.