What is the primary role of keratinocytes in the skin?

Keratinocytes play a vital role in forming the outermost layer of the skin, known as the epidermis. Their primary function is to produce keratin, a fibrous protein that is essential for creating a protective barrier against external threats such as pathogens, chemicals, and physical injury. This barrier also helps to prevent water loss, which is crucial for maintaining hydration.

As keratinocytes differentiate and move up through the layers of the epidermis, they become more flattened and filled with keratin, leading to the formation of a tough, impermeable layer that contributes to the integrity and resilience of the skin. This process is key to skin health and function, making the protective barrier one of the most critical roles of keratinocytes.

While other cell types in the skin are responsible for functions such as producing melanin (which is performed by melanocytes), sensing pressure (which involves specialized nerve endings), and activating immune responses (which is mainly the role of Langerhans cells and other immune cells in the skin), the primary role of keratinocytes is centered around barrier formation, underscoring their importance in skin physiology.