keratinocite

Keratinocite is not a standard term in scientific literature and is likely a misspelling or variant of keratinocyte, the principal cell type of the epidermis. Keratinocytes make up the majority of epidermal cells and play a central role in forming the skin’s barrier.

Keratinocytes originate in the stratum basale, the deepest layer of the epidermis, where they divide to produce new cells. These cells migrate upward through the epidermal layers, undergoing differentiation as they go. In healthy adult skin, the journey from basal division to shedding at the surface takes roughly 28 to 30 days.

Biochemically, keratinocytes express different keratin proteins as they mature. Basal keratinocytes primarily express keratins 5 and 14, while suprabasal cells express keratins 1 and 10. As they mature, keratinocytes keratinize to form the stratum corneum, a tough outer layer of dead cells. In the granular layer, they accumulate keratohyalin and release lipids via lamellar bodies, helping establish the skin’s hydrophobic barrier.

Keratinocytes contribute to barrier function through intercellular junctions such as desmosomes and tight junctions, and by producing lipids and antimicrobial peptides. They also participate in cutaneous immune responses by secreting cytokines and chemokines in response to injury or infection.

Impaired keratinocyte function or abnormal proliferation underlies several skin conditions, including psoriasis, eczema, ichthyosis, and certain skin cancers such as squamous cell carcinoma. Because of their central role in barrier integrity and immunity, keratinocytes are a major focus of dermatological research.