Keratins Stabilize Hemidesmosomes through Regulation of beta 4-Integrin Turnover

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Seltmann K, Cheng F, Wiche G, Eriksson JE, Magin TM
Publication year: 2015
Journal: Journal of Investigative Dermatology
Journal acronym: J INVEST DERMATOL
Volume number: 135
Issue number: 6
Start page: 1609
End page: 1620
Number of pages: 12
ISSN: 0022-202X
eISSN: 1523-1747


Epidermal integrity and wound healing depend on remodeling of cell-matrix contacts including hemidesmosomes. Mutations in beta 4-integrin and plectin lead to severe epidermolysis bullosa (EB). Whether mutations in keratins K5 or K14, which cause EB simplex, also compromise cell-matrix adhesion through altering hemidesmosomal components is not well investigated. In particular, the dependence of beta 4-integrin endocytosis and turnover on keratins remains incompletely understood. Here, we show that the absence of keratins causes loss of plectin-beta 4-integrin interaction and elevated beta 4-integrin phosphorylation at Ser1354 and Ser1362. This triggered a caveolin-dependent endocytosis of beta 4-integrin but not of other integrins through Rab5 and Rab11 compartments in keratinocytes. Expressing a phospho-deficient beta 4-integrin mutant reduces beta 4-integrin endocytosis and rescues plectin localization in keratin-free cells. beta 4-integrin phosphorylation in the absence of keratins resulted from elevated Erk1/2 activity downstream of increased EGFR and PKC alpha signaling. Further, increased Erk1/2 phosphorylation and altered plectin localization occur in keratin-deficient mouse epidermis in vivo. Strikingly, expression of the K14-R125P EBS mutant also resulted in plectin mislocalization and elevated beta 4-integrin turnover, suggesting disease relevance. Our data underscore a major role of keratins in controlling beta 4-integrin endocytosis involving a plectin-Erk1/2-dependent mechanism relevant for epidermal differentiation and pathogenesis.

Last updated on 2020-31-03 at 08:15