Cornified Epithelial Teeth of Jawless Vertebrates Contain Proteins Similar to Keratin-Associated Proteins of Mammalian Skin Appendages

The study examines the presence of keratin-associated protein-like (KRTAPL) proteins in the cornified epithelial teeth of jawless vertebrates, specifically lampreys, using mass spectrometry-based proteomics. These proteins share similarities with mammalian keratin-associated proteins (KRTAPs) found in hair and nails, such as high cysteine and tyrosine content, but differ in gene structure, having two exons instead of one. The research suggests that these proteins evolved through convergent evolution, indicating an evolutionary parallel in the development of structural proteins across different species. The study highlights the need for further research into the expression and function of KRTAPLs in lampreys.