title: Polarized distribution of inducible nitric oxide synthase regulates activity in intestinal epithelial cells.
abstract: Inducible nitric oxide synthase (iNOS) functions as a homodimer. In cell extracts, iNOS molecules partition both in cytosolic and particulate fractions, indicating that iNOS exists as soluble and membrane associated forms. In this study, iNOS features were investigated in human intestinal epithelial cells stimulated with cytokines and in duodenum from mice exposed to flagellin. Our experiments indicate that iNOS is mainly associated with the particulate fraction of cell extracts. Confocal microscopy showed a preferential localization of iNOS at the apical pole of intestinal epithelial cells. In particulate fractions, iNOS dimers were more abundant than in the cytosolic fraction. Similar observations were seen in mouse duodenum samples. These results suggest that, in epithelial cells, iNOS activity is regulated by localization-dependent processes.
authors.affiliation: Swiss Experimental Cancer Research Center, Epalinges, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Rumbo
authors.forename: Françoise
authors.initials: F
authors.lastname: Courjault-Gautier
authors.forename: Frédéric
authors.initials: F
authors.lastname: Sierro
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Sirard
authors.forename: Emanuela
authors.initials: E
authors.lastname: Felley-Bosco
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D019281:Dimerization; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II
chemical_list: C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse