Biochemical Evidence That Small Proline-Rich Proteins and Trichohyalin Function in Epithelia by Modulation of the Biomechanical Properties of Their Cornified Cell Envelopes

The study provided biochemical evidence that small proline-rich proteins (SPRs) and trichohyalin (THH) played crucial roles in modulating the biomechanical properties of cornified cell envelopes (CEs) in epithelia. The research focused on mouse forestomach CEs, which were found to contain high levels of cross-linked proteins, including loricrin and SPRs. These proteins functioned as cross-bridging elements, using their head and tail domains for cross-linking, thereby contributing to the toughness and flexibility of the CEs. The study highlighted that the composition and cross-linking of these proteins varied across different epithelial tissues, correlating with their mechanical requirements. This suggested that SPRs and THH were significant in determining the physical properties of epithelial tissues, providing insights into their structural roles.