COLOCALIZATION OF STOMATIN (BAND 7.2B) AND ACTIN MICROFILAMENTS IN UAC EPITHELIAL-CELLS

Cytolocalization of stomatin, an integral membrane protein also called erythrocyte band 7.2b, was investigated in a human epithelial cell li ne in which the expression of this protein is up-regulated after treat ment with interleukin-6 and dexamethasone. A monoclonal antibody again st stomatin was used to perform immunofluorescence and immunoelectron microscopy. The data show that stomatin concentrates preferentially in small plasma membrane protrusions. It is also found in abundance in a juxtanuclear structure possibly derived from the Golgi apparatus. Flu orescent double staining using the anti-stomatin antibody and the acti n binding drug phalloidin shows a significant degree of colocalization of stomatin and cortical actin microfilaments. This association remai ns after actin filament disruption by cytochalasin D treatment indicat ing a strong connection between stomatin and the membrane-associated c ytoskeleton.