KRTAP15-1 is a keratin-associated protein (KRTAP) located on chromosome 21. Based on limited published evidence, KRTAP15-1 functions in the hair cortex as a structural component of the interfilamentous matrix surrounding hair keratin intermediate filaments. Through extensive disulfide bond cross-linking with cysteine-rich hair keratins, KRTAP15-1 contributes to forming rigid and resistant hair shafts 1. The protein exhibits cytosolic localization and protein-binding capacity. KRTAP15-1 is genomically positioned near KRTAP13 family members, suggesting coordinated regulation of hair structure.