Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nitric oxide (NO) has been reported to be involved in the regulation of pseudopodia formation, phagocytosis and adhesion in macrophages through the reorganization of actin. In the present study, we directly separated the globular (G) and filamentous (F) actin from quiescent or NO-stimulated macrophage-like cell line RAW 264.7 cells in order to investigate the dynamic redistribution of actin pools. We also focused on the regulatory mechanisms of actin assembly, induced by NO and its possible subsequent signaling pathway. We showed that predominant G-actin coexisted with Triton X-100-insoluble filamentous (TIF) and Triton X-100-soluble filamentous actin in resting RAW 264.7 cells. The exogenous NO produced by (+/-)-(E)-2-[(E)-hydroxyimino]-6-methoxy-4-methyl-5-nitro-3-hexenamide (NOR1), the endogenous NO induced by lipopolysaccharide (LPS) plus interferon-gamma (IFNgamma), and dibutyryl-cGMP increased the contents of TIF-actin in dose- and time-dependent manners and altered its morphology. The increase in the TIF-actin contents induced by NOR1 or LPS plus IFNgamma was efficiently blocked by the radical scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide and the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one or the arginine analogue N(G)-monomethyl-L-arginine acetate, respectively. Preincubation with the calmodulin antagonist W-7 almost completely blocked the NO-induced TIF-actin increase and morphological change. On the other hand, preincubation with C3 transferase, an inhibitor of Rho protein, efficiently prevented the change in cell morphology, but had no effect on the TIF-actin increase. We postulate that cGMP and subsequent Ca(2+)/calmodulin may be key regulators of actin reorganization in NO-stimulated RAW 264.7 cells.
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PMID:Nitric oxide regulates actin reorganization through cGMP and Ca(2+)/calmodulin in RAW 264.7 cells. 1138 72

We have recently demonstrated that nitric oxide (NO) produced by neuronal NO synthase (nNOS) in the spinal cord is involved in the maintenance of neuropathic pain. To clarify whether NO itself affected nNOS activity in the spinal cord as a retrograde messenger, we examined the involvement of the NO/cGMP signaling pathway in the regulation of nNOS activity by NADPH-diaphorase histochemistry. NO-generating agents NOR3 (t(1/2)=30min) and SNAP (t(1/2)=5h), but not NOR1 (t(1/2)=1.8min), significantly enhanced NADPH-diaphorase staining in the spinal cord. 8-Br-cGMP also enhanced it similar to that by NOR3, and 8-Br-cAMP and forskolin, an activator of adenylate cyclase, enhanced it moderately. NOR1 and NOR3 markedly increased the cGMP level in the spinal cord. The enhancement of NADPH-diaphorase staining by NOR3 was significantly inhibited by CPTIO, an NO scavenger, ODQ, a soluble guanylate cyclase inhibitor, and KT5823, an inhibitor of cGMP-dependent protein kinase. Additionally, the NOR3-enhanced nNOS activity was completely inhibited by NMDA antagonists MK-801 and d-AP5, partially by the GluRepsilon2-selective antagonist CP-101,606, and was attenuated in GluRepsilon1(-/-) and GluRepsilon1(-/-)/epsilon4(-/-) mice. These results suggest that NO may regulate nNOS activity as a retrograde messenger in the spinal cord via activation of NMDA receptor containing GluRepsilon1 and GluRepsilon2 subunits.
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PMID:Nitric oxide (NO) serves as a retrograde messenger to activate neuronal NO synthase in the spinal cord via NMDA receptors. 1754 18