| Abstract: | Epithelial PtK2 cells were used as a model to study the possible redistribution of the major tyrosine protein kinase substrate, p36, upon drug-induced reorganization of the cytokeratin network. Cells were grown on glass coverslips and exposed to cytochalasin D (CD), colcemid or a combination of the two. The cytokeratin type intermediate filaments of the cells were redistributed by treatment of the cells with colchicine and CD. Simultaneous changes in cytokeratin and in p36 antigen were observed by double-label immunofluorescence. In control PtK2 cells, p36 was distributed characteristically at the cortical cytoplasm. Neither colchicine nor CD alone was able to cause a major reorganization of cytokeratin or p36. Their combined effect resulted in formation of blebs containing abundant p36 at the cell surface and at cell-cell junctions. Actin, on the other hand, was reorganized to similar configurations by CD alone. These observations show for the first time a drug-induced redistribution of p36. The results suggest a relationship between membrane-associated p36 and the cytoskeletal fibres that terminate at the plasma membrane. |
