ACTIN IN STRATIFIED SQUAMOUS KERATINIZED EPITHELIUM

Actin filament distribution patterns were revealed in a stratified squ amous keratinized epithelium using phalloidin-fluorescent and immunogo ld labeling techniques applied on bovine ruminal pilar as a model tiss ue. In non-keratinized cell types, actin concentrates on the microfila ment-rich cellular cortex as well as on cytoplasmic processes and prot rusions. In cornified cells labeling is distributed diffusely over the amorphous cytoplasm. A constant feature in all cell types is plasmale mmal labeling. Desmosomes exhibit deposition on their plasmalemmal lea flets, the dense central stratum and plaques. Desmosomal as well as cy toplasmic keratinfilament bundles also label for actin, the latter oft en in a cross-banded manner. These cellular distribution patterns of a ctin filaments are discussed with respect to the significance of the m icrofilaments in the process of cell shape determination, stratificati on, and cell adhesion.