Expression of Novel Keratin-Associated Protein 5 Genes in the Cuticle Layer of Human Hair Follicles

The study focused on the expression of novel keratin-associated protein 5 (KAP5) genes in the cuticle layer of human hair follicles. Hair keratin proteins and KAPs are crucial structural components of hair fibers, with KAPs functioning as disulfide bond cross-linking proteins. While previous research identified two KAP5 genes on human chromosome 11, this study mapped nine additional KAP5 members on chromosomes 11p15.5 and 11q13.5. Using RT-PCR, the expression of all KAP5 genes in hair roots was confirmed, but their detailed distribution within hair follicles was not previously explored. This study compared the expression sites of five KAP5 genes on chromosome 11q13.5 using scalp skin sections, providing new insights into their specific localization in hair follicles.