Follicular keratin (None standardized; commonly referenced by specific keratin types (e.g., K6, K71-K75))

Follicular keratin is a family of alpha-helical structural proteins that form intermediate filaments within hair follicles and epithelial tissues. These proteins, including specific types such as K6, K71-K75, and others, assemble into a hierarchical structure comprising central coiled-coil dimers that polymerize into 10-nanometer filaments. In hair structure, keratin filaments aggregate to form the cortex (approximately 90% of hair volume) and interact with keratin-related proteins (KRTAPs) to create a cross-linked matrix that provides the hair shaft with its mechanical rigidity and structural stability. Follicular keratins also play critical roles in cell-to-cell adhesion through desmosome complexes and participate in broader cellular processes including signaling and vesicle transport. Rather than serving as a druggable therapeutic target, follicular keratin functions as a fundamental structural component whose proper assembly and expression are essential for hair integrity and epithelial tissue function.

Other names

Hair keratinKeratin filamentAlpha-keratin (α-keratin)Specific types: K6K71 (K6irs1)K72 (K6irs2)K73 (K6irs3)K74 (K6irs4)K75 (K6hf)

Not applicable - follicular keratin is not a therapeutic target for drug mechanisms of action.