Wool Fiber Curvature Is Correlated With Abundance of K38 and Specific Keratin-Associated Proteins

The study investigates the relationship between wool fiber curvature and protein composition by examining progeny of straight-wool domestic sheep mutants and wild-type ewes. It finds that straight crimp mutant wool, while having a normal cuticle and similar cortical protein and ultrastructural components as wild-type wool, differs in the layout of cortical cells and the relative proportions of keratin (K) and keratin-associated proteins (KAPs). Specifically, crimp mutants show a fragmented orthocortex distribution and altered protein abundance, with reduced levels of KAP6, KAP7, KAP8, and K38, and increased levels of KAP16, KAP19, KAP4, and KAP9. This suggests that fiber curvature is correlated with specific protein compositions and distributions.