Trichohyalin, an Intermediate Filament-Associated Protein of the Hair Follicle

The study isolated and characterized a 190,000 molecular weight protein, termed trichohyalin, from sheep wool follicles. This protein, rich in lysine, glutamic acid/glutamine, and arginine residues, was found to undergo a side chain conversion to citrulline residues. Polyclonal antibodies raised against this protein cross-reacted with similar proteins in guinea pig, human follicles, and rat vibrissae inner root sheaths. Immunochemical methods localized trichohyalin to the trichohyalin granules of the developing inner root sheath, suggesting its role as a matrix protein associated with intermediate filaments at later stages of development.