Ancient Lineages of the Keratin-Associated Protein (KRTAP) Genes and Their Co-option in the Evolution of the Hair Follicle
November 2022
in “
Research Square (Research Square)
”
TLDR Keratin-associated proteins have ancient origins and were used for different purposes before being adapted for hair in mammals.
The document provides an in-depth analysis of the evolutionary history and functions of keratin-associated proteins (KRTAPs), revealing that these proteins have ancient origins and are not exclusive to hair formation in mammals. It was found that 53 out of 93 human KRTAPs are similar to metallothionein and 16 to occludin, with the metallothionein-linked KRTAPs present in ancient deuterostomes and the occludin-linked KRTAPs appearing later in mollusca. The study suggests that KRTAPs may have had different functions in non-hairy animals before being co-opted for hair follicle development in mammals. It also highlights the role of the ectodysplasin (EDA) pathway, which is essential for the development of ectodermal organs and originated in jawless fishes. The research indicates that KRTAPs and the EDA pathway had roles in organisms prior to the evolution of hair. Additionally, the study found that in humans, M lineage KRTAPs have significantly higher expression in skin than O lineage KRTAPs and that in alopecia patients, M lineage KRTAP expression was 50% higher than O lineage. The document is based on analyses of public databases and does not report new experimental data.
