Convergent Evolution of Cysteine-Rich Keratins in Horny Teeth of Jawless Vertebrates and in Cornified Skin Appendages of Amniotes.

ABSTRACT: Cornified skin appendages, such as claws and hair, of amniotes consist of keratins with high numbers of cysteine residues, which serve as sites of protein cross-linking through disulfide bonds. Here, we show by proteomic analysis that cysteine-rich keratins are also components of the horny teeth of the sea lamprey (Petromyzon marinus), a jawless vertebrate. The cysteine-rich keratins of the lamprey are conserved in hagfish, which diverged from lampreys around 460 million years ago. Phylogenetic analysis confirmed the orthology of the cysteine-rich keratins of lampreys and hagfish (cyclostomes) and showed that cysteine-rich keratins of amniotes belong to different clades of keratins. We conclude that keratins with elevated cysteine content evolved not only in amniotes but also, and much ear

SUBMITTER: Sachslehner AP 

PROVIDER: S-EPMC11850651 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature