Mitochondria to nucleus stress signaling: a distinctive mechanism of NFkappaB/Rel activation through calcineurin-mediated inactivation of IkappaBbeta.
Mitochondrial genetic and metabolic stress causes activation of calcineurin (Cn), NFAT, ATF2, and NFkappaB/Rel factors, which collectively alter the expression of an array of nuclear genes. We demonstrate here that mitochondrial stress-induced activation of NFkappaB/Rel factors involves inactivation of IkappaBbeta through Cn-mediated dephosphorylation. Phosphorylated IkappaBbeta is a substrate for Cn phosphatase, which was inhibited by FK506 and RII peptide. Chemical cross-linking and coimmunoprecipitation show that NFkappaB/Rel factor-bound IkappaBbeta forms a ternary complex with Cn under in vitro and in vivo conditions that was sensitive to FK506. Results show that phosphorylation at S313 and S315 from the COOH-terminal PEST domain of IkappaBbeta is critical for binding to Cn. Mutations at S313/S315 of IkappaBbeta abolished Cn binding, inhibited Cn-mediated increase of Rel proteins in the nucleus, and had a dominant-negative effect on the mitochondrial stress-induced expression of RyR1 and cathepsin L genes. Our results show the distinctive nature of mitochondrial stress-induced NFkappaB/Rel activation, which is independent of IKKalpha and IKKbeta kinases and affects gene target(s) that are different from cytokine and TNFalpha-induced stress signaling. The results provide new insights into the role of Cn as a critical link between Ca2+ signaling and NFkappaB/Rel activation.
Dept. of Animal Biology, Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Gopa
G
Biswas
Hindupur K
HK
Anandatheerthavarada
Mone
M
Zaidi
Narayan G
NG
Avadhani
D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000235:genetics; D019703:Calcineurin / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000235:genetics*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005057:Eukaryotic Cells / Q000187:drug effects / Q000378:metabolism; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D020572:Oncogene Proteins v-rel / Q000235:genetics / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects / Q000235:genetics; D012694:Serine / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
D004791:Enzyme Inhibitors; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D016328:NF-kappa B; D020572:Oncogene Proteins v-rel; D014409:Tumor Necrosis Factor-alpha; D012694:Serine; D019703:Calcineurin; D010749:Phosphoprotein Phosphatases