title: α7 nicotinic acetylcholine receptors control cytochrome c release from isolated mitochondria through kinase-mediated pathways.
abstract: Nicotinic acetylcholine receptors are ligand-gated ion channels found in the plasma membrane of both excitable and non-excitable cells. Previously we reported that nicotinic receptors containing α7 subunits were present in the outer membranes of mitochondria to regulate the early apoptotic events like cytochrome c release. Here we show that signaling of mitochondrial α7 nicotinic receptors affects intramitochondrial protein kinases. Agonist of α7 nicotinic receptors PNU 282987 (30 nM) prevented the effect of phosphatidyl inositol-3-kinase inhibitor wortmannin, which stimulated cytochrome c release in isolated mouse liver mitochondria, and restored the Akt (Ser 473) phosphorylation state decreased by either 90 μM Ca(2+) or wortmannin. The effect of PNU 282987 was similar to inhibition of calcium-calmodulin-dependent kinase II (upon 90 μM Ca(2+)) or of Src kinase(s) (upon 0.5mM H2O2) and of protein kinase C. Cytochrome c release from mitochondria could be also attenuated by α7 nicotinic receptor antagonist methyllicaconitine or α7-specific antibodies. Allosteric modulator PNU 120526 (1 μM) did not improve the effect of agonist PNU 282987. Acetylcholine (1 μM) and methyllicaconitine (10nM) inhibited superoxide release from mitochondria measured according to alkalization of Ca(2+)-containing medium. It is concluded that α7 nicotinic receptors regulate mitochondrial permeability transition pore formation through ion-independent mechanism involving activation of intramitochondrial PI3K/Akt pathway and inhibition of calcium-calmodulin-dependent or Src-kinase-dependent signaling pathways.
authors.affiliation: Palladin Institute of Biochemistry, 9, Leontovicha Str., Kyiv 01601, Ukraine.
authors.forename: Galyna
authors.initials: G
authors.lastname: Gergalova
authors.affiliation: Palladin Institute of Biochemistry, 9, Leontovicha Str., Kyiv 01601, Ukraine.
authors.forename: Olena
authors.initials: O
authors.lastname: Lykhmus
authors.affiliation: Palladin Institute of Biochemistry, 9, Leontovicha Str., Kyiv 01601, Ukraine.
authors.forename: Sergiy
authors.initials: S
authors.lastname: Komisarenko
authors.affiliation: Palladin Institute of Biochemistry, 9, Leontovicha Str., Kyiv 01601, Ukraine. Electronic address: skok@biochem.kiev.ua.
authors.forename: Maryna
authors.initials: M
authors.lastname: Skok
mesh_terms: D000157:Aconitine / Q000031:analogs & derivatives / Q000494:pharmacology; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D018722:Nicotinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D013481:Superoxides / Q000378:metabolism; D000077191:Wortmannin; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000157:Aconitine; D000730:Androstadienes; D001549:Benzamides; D001643:Bridged Bicyclo Compounds; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D045304:Cytochromes c; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D051057:Proto-Oncogene Proteins c-akt; D013481:Superoxides; D000077191:Wortmannin; D064569:alpha7 Nicotinic Acetylcholine Receptor; D019061:src-Family Kinases; C498513:PNU-282987; C054634:methyllycaconitine
keywords: Cytochrome c; Mitochondria; Nicotinic acetylcholine receptor; Protein kinases; Superoxide