IMMUNOCYTOCHEMICAL STUDY OF EZRIN IN CULTURED MADIN-DARBY CANINE KIDNEY-CELLS

Monoclonal antibody for ezrin was used to study the intracellular loca lization and distribution of ezrin in Madin-Darby canine kidney cells. Immunocytochemical study showed that ezrin was highly concentrated in microvillous and cell-to-cell adhesion sites. Using sorbitol gradient for cell fractionation, ezrin was mostly recovered in the plasma memb rane-enriched fraction. Western blot analysis showed that the monoclon al antibody reacted only with the 81 K protein, which is one of ERM fa mily proteins in MDCK cells. These data were consistent with immunoflu orescence microscopic observation. Immunostaining pattern of cells usi ng anti-ezrin mAb was very similar to that for F-actin as shown by a d ouble-labelling technique. Treatment of the cells with cytochalasin B revealed disruption of the intracellular distribution of F-actin and e zrin.