Intermediate filaments and their interaction with membranes. The desmosome-cytokeratin filament complex and...

Intermediate-sized filaments represent a class of morphologically similar but biochemically and immunologically distinguishable cytoplasmic protein polymer structures. Five major filament types have been identified (cytokeratin, vimentin, desmin, neurofilament protein, glia filament protein) and antibodies to these proteins have been used for distinguishing different cell types and tumors derived therefrom. Epithelial and carcinoma cells are characterized by the presence of cytokeratin filaments and desmosomal elements identified by antibodies to certain high molecular weight proteins of desmosomal plaques. However, the specific pattern of cytokeratin polypeptides is different in different epithelia. The potential value of cell type identification by immunological reactions with antibodies to cytoskeletal proteins in tumor diagnosis is discussed.