Based on limited published evidence, KRTAP6-1 encodes a keratin-associated protein (KAP) that plays a structural role in hair shaft formation. According to UniProt annotations, KRTAP6-1 is embedded in the interfilamentary matrix of hair cortex, where it cross-links with hair keratins through extensive disulfide bonding to form rigid, resistant hair shafts 1. The protein localizes to the cytosol and exhibits protein binding capacity. In wool follicles, KRTAP6-1 is expressed during anagen growth and is specifically required for cortical cell formation in the brush-end anchoring structure 1. Expression is sequentially regulated during follicle cycling stages.