Epidermis-specific type I keratin that plays a key role in skin (PubMed:22336941, PubMed:24218583). Acts as a regulator of innate immunity in response to skin barrier breach: required for some inflammatory checkpoint for the skin barrier maintenance (PubMed:24218583). Heterodimer of a type I and a type II keratin. KRT16 associates with KRT6 isomers (KRT6A or KRT6B) (PubMed:8636216). Interacts with TCHP (By similarity). Interacts with TRADD (PubMed:16702408). Expressed in the epithelia of the tongue, upper and lower palate, footpad, proximal nail fold and nail bed, penile spine, sweat gland ducts, and back epidermis (at protein level) (PubMed:12445204). Expressed in upper suprabasal layers of the corneal epithelium (at protein level) (PubMed:26758872). Expressed in internal stratified epithelia in the esophagus and vagina (at protein level) (PubMed:12445204). Expressed in transitional stratified squamous epithelia in the forestomach, anal canal, and nasal cavity (at protein level) (PubMed:12445204). Expressed in transitional epithelia of the ureter, bladder and urethra (at protein level) (PubMed:12445204). In mature hair follicles, expressed in the companion layer of the outer root sheath during anagen and in the club hair sheath during catagen and telogen (at protein level) (PubMed:12445204). During embryonic development, initially localizes within early hair germs, but rapidly shifts to a subset of cells at the interface of basal and suprabasal cells above and around the hair germ (PubMed:12445204). Expressed in hair follicles and in most cells in the spinous layer at birth (PubMed:11408584). In response to epidermal stress such as wounding. Mice were born alive at approximately Mendelian ratios but increased postnatal mortality is observed. Surviving mice show oral lesions as well as palmoplantar keratoderma-like hyperkeratotic calluses on front and hind paws, which impair the ability to walk. There are two types of cytoskeletal and microfibrillar keratin: I (acidic; 40-55 kDa) and II (neutral to basic; 56-70 kDa). Belongs to the intermediate filament family.