title: Contraction of isolated brush borders from the intestinal epithelium.
abstract: Brush borders isolated from epithelial cells from the small intestine of neonatal rats are able to contract in the presence of ATP and Mg2+; Ca2+ is not required. Contraction is characterized by a pinching-in of the plasma membrane in the region of the zonula adherens and a subsequent rounding of the brush borders. No movement or consistent shortening of the microvilli is observed. The contraction appears to involve the 5- to 7-nm diameter microfilaments in the terminal web which associate with the zonula adherens. These filaments bind heavy meromyosin as do the actin core filaments of the microvilli. A model for contraction is presented in which, in the intact cell, terminal web filaments and core filaments interact to produce shortening of the microvilli.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D002465:Cell Movement; D007365:Intercellular Junctions / Q000648:ultrastructure; D007413:Intestinal Mucosa / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D008954:Models, Biological; D015879:Myosin Subfragments / Q000378:metabolism; D051381:Rats
chemical_list: D015879:Myosin Subfragments