Intracellular formation of ”undisruptable” dimers of inducible nitric oxide synthase
Authors:
- 12 November 2003
- journal article
- Published by National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 100 (24) , 14263-14268
Abstract
Overproduction of nitric oxide (NO) by inducible NO synthase (iNOS) has been implicated in the pathogenesis of many diseases. iNOS is active only as a homodimer. Dimerization of iNOS represents a potentially critical target for therapeutic intervention. In this study, we show that intracellular iNOS forms dimers that are ”undisruptable” by boiling, denaturants, or reducing agents. Undisruptable (UD) dimers are clearly distinguishable from the easily dissociated dimers formed by iNOSin vitro. UD dimers do not form inEscherichia coli-expressed iNOS and could not be assembledin vitro, which suggests that anin vivocellular process is required for their formation. iNOS UD dimers are not affected by intracellular depletion of H4B. However, the mutation of Cys-115 (critical for zinc binding) greatly affects the formation of UD dimers. This study reveals insight into the mechanisms ofin vivoiNOS dimer formation. UD dimers represent a class of iNOS dimers that had not been suspected. This unanticipated finding revises our understanding of the mechanisms of iNOS dimerization and lays the groundwork for future studies aimed at modulating iNOS activityin vivo.Keywords
This publication has 39 references indexed in Scilit:
- Pharmacological Interference with Dimerization of Human Neuronal Nitric-Oxide Synthase Expressed in Adenovirus-Infected DLD-1 CellsMolecular Pharmacology, 2003
- Distinct Dimer Interaction and Regulation in Nitric-oxide Synthase Types I, II, and IIIJournal of Biological Chemistry, 2002
- Inducible Nitric-oxide Synthase Is Regulated by the Proteasome Degradation PathwayJournal of Biological Chemistry, 2001
- Crystal Structures of Zinc-free and -bound Heme Domain of Human Inducible Nitric-oxide SynthaseJournal of Biological Chemistry, 1999
- INHIBITION OF NITRIC OXIDE SYNTHASE AS A POTENTIAL THERAPEUTIC TARGETAnnual Review of Pharmacology and Toxicology, 1999
- Crystal Structure of Constitutive Endothelial Nitric Oxide SynthaseCell, 1998
- Characterization of the Inducible Nitric Oxide Synthase Oxygenase Domain Identifies a 49 Amino Acid Segment Required for Subunit Dimerization and Tetrahydrobiopterin InteractionBiochemistry, 1997
- Macrophage NO synthase: characterization of isolated oxygenase and reductase domains reveals a head-to-head subunit interactionBiochemistry, 1995
- Cloning and Characterization of Inducible Nitric Oxide Synthase from Mouse MacrophagesScience, 1992
- Zinc coordination, function, and structure of zinc enzymes and other proteinsBiochemistry, 1990