Evidence for the association of villin with core filaments and rootlets of intestinal epithelial microvilli.
Villin, a 95,000 dalton polypeptide of intestinal brush border which is known to bundle or sever actin filaments in a Ca++-dependent manner, was localized in rat and chicken intestinal epithelium by means of immunocytochemistry at the light- and electron-microscopic levels. Specific antibodies to villin were raised in rabbits immunized with villin purified from chicken intestinal epithelium. Anti-villin bound selectively to the microvillus filament bundle from its tip down to the rootlets. These findings indicate that the well-known stability of rootlet filaments towards elevated Ca++ ion concentrations cannot be explained by the absence of villin. Therefore additional factors must exist which prevent the rootlets from Ca++-villin mediated disassembly.
D000818:Animals; D002135:Calcium-Binding Proteins / Q000032:analysis*; D002352:Carrier Proteins / Q000032:analysis*; D002462:Cell Membrane / Q000032:analysis*; D002645:Chickens; D004848:Epithelium / Q000032:analysis; D005455:Fluorescent Antibody Technique; D007413:Intestinal Mucosa / Q000032:analysis*; D008840:Microfilament Proteins; D008871:Microvilli / Q000032:analysis* / Q000648:ultrastructure; D051381:Rats
D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D008840:Microfilament Proteins; C026615:villin