Reciprocal modulation of aconitase activity and RNA-binding activity of iron regulatory factor by nitric oxide.

Abstract

The recent discovery that nitric oxide (NO) is synthetized by many cell types has focused a lot of attention on this gaseous radical thus far considered as highly toxic. NO plays a role in major vital functions including the regulation of vascular tone, the non-specific immune defense and neurotransmission. This wide range of physiological functions has been extensively reviewed recently (Hibbs et al., 1990; Moncada et al., 1991; Nathan, 1992) and will not be developped. However, it is important to recall that many isoforms of NO synthases have been described and are coded by at least three genes (Nathan, 1992). Functionally, two main types exist: one is constitutively expressed and produces low amount of NO (picomolar range) in response to calcium elevation. The other one is induced at the transcriptional level after a lag of several hours and produces far larger amount of NO (nanomolar range). The main molecular target of NO produced in minute amounts by the constitutive NO synthase is a soluble, heme-dependent guanylate cyclase. Resulting increase of cGMP results in a cascade of events leading to physiological effects including vasodilation and synaptic plasticity (Moncada et al., 1991; Bredt and Snyder, 1992).KeywordsNitric OxideElectron Paramagnetic ResonanceTyrosyl RadicalAconitase ActivityClostridium PasteurianumThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.