Keratin function in skin epithelia: a broadening palette with surprising shades.
Keratins make up the largest subgroup of intermediate filament (IF) proteins and form a dynamic network of 10-12 nm filaments, built from type I/type II heterodimers, in the cytoplasm of epithelial cells. A major function of keratin IFs is to protect epithelial cells from mechanical and non-mechanical stresses that cause cell rupture and death. Interference with this role is the root cause of a large number of inherited epithelial fragility conditions. Additional functions, non-mechanical in nature, are manifested in a way that depends on the specific keratin and on the epithelial context. The recent discovery of unusual mutations affecting keratin proteins has uncovered a novel dimension of their mechanical support function, and has synergized with mouse genetics to reveal a role in skin pigmentation. Other studies extended the role of keratin proteins in regulating the response to pro-apoptotic signals, and revealed their ability to modulate protein synthesis and cell size in epithelial cells challenged to grow.
Gu
Li-Hong
LH
Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA.
Coulombe
Pierre A
PA
D000818:Animals; D049109:Cell Proliferation; D004847:Epithelial Cells / Q000502:physiology; D004848:Epithelium / Q000378:metabolism; D018859:Hair Follicle / Q000502:physiology; D006801:Humans; D007382:Intermediate Filaments / Q000235:genetics / Q000378:metabolism; D007633:Keratins / Q000235:genetics / Q000502:physiology*; D008543:Melanins / Q000378:metabolism; D009154:Mutation; D014176:Protein Biosynthesis; D012867:Skin / Q000378:metabolism*; D009626:Terminology as Topic
D008543:Melanins; D007633:Keratins