Useful markers of epithelial differentiation are
Fillagrin
Loricin
Both
None
The protein making the bulk of keratohyalin granules is fillagrin. Also sulfur-rich protein loricin is present.  Fillagrin and loricin are useful markers of epithelial differentiation. Involucrin contributes to the 'Cornified cell envelope' in the cell membrane of keratohyalin cells.