Expression of beta-catenin and integrin-linked kinase in the mouse sciatic nerve

In the present study, the expressions of beta-catenin and integrin-linked kinase (ILK) in the adult mouse peripheral nerve were investigated by means of immunoblotting analyses and electron microscopy using the immunogold pre -embedding method. As a result, beta-catenin and ILK were shown to be expressed both in the axon and the Schwann cell of the myelinated and unmyelinated fibers. By electron microscopy, some molecules of beta-catenin and ILK tended to concentrate under the axolemma in the unmyelinated fibers, while these molecules were distributed in a scattered form throughout the axoplasm in the myelinated fibers. Concerning the cytoplasm of the Schwann cells, the loop region was too slender to detect whether beta-catenin and ILK were associated with the plasmalemma; however, beta-catenin and ILK were distributed diffusely without any relationship in regard to the plasmalemma or the cell organelles around the nucleus region. The density of beta-catenin and ILK around the nucleus region was greater than that within the nucleus region. From these results, some molecules of beta-catenin mediate the axon-Schwann cell adhesion of the unmyelinated fibers, while other molecules are thought to be separated from the cadherin-catenin complex on the plasmalemma. Accordingly, it is hypothesized that the cell-cell adhesion property in the peripheral nerve is not strong but dynamic, and this adhesion is possibly regulated by ILK.