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Regulation of intermediary metabolism by the PKCδ signalosome in mitochondria
Author(s) -
Acin-Perez Rebeca,
Hoyos Beatrice,
Gong Jianli,
Vinogradov Valerie,
Fischman Donald A.,
Leitges Michael,
Borhan Babak,
Starkov Anatoly,
Manfredi Giovanni,
Hammerling Ulrich
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.10.166934
Subject(s) - protein kinase c , mitochondrion , microbiology and biotechnology , signal transduction , phosphorylation , biology , dephosphorylation , oxidative phosphorylation , cytochrome c , pyruvate dehydrogenase complex , biochemistry , chemistry , enzyme , phosphatase
ABSTRACT PKCδ has emerged as a novel regulatory molecule of oxidative phosphorylation by targeting the pyruvate dehydrogenase complex (PDHC). We showed that activation of PKCδ leads to the dephosphorylation of pyruvate dehydrogenase ki‐nase 2 (PDK2), thereby decreasing PDK2 activity and increasing PDH activity, accelerating oxygen consumption, and augmenting ATP synthesis. However, the molecular components that mediate PKCδ signaling in mitochondria have remained elusive so far. Here, we identify for the first time a functional complex, which includes cytochrome c as the upstream driver of PKCδ, and uses the adapter protein p66Shc as a platform with vitamin A (retinol) as a fourth partner. All four components are necessary for the activation of the PKCδ signal chain. Genetic ablation of any one of the three proteins, or retinol depletion, silences signaling. Furthermore, mutations that disrupt the interaction of cytochrome c with p66Shc, of p66Shc with PKCδ,orthe deletion of the retinol‐binding pocket on PKCδ, attenuate signaling. In cytochrome c‐deficient cells, reintroduction of cytochrome c Fe 3+ protein restores PKCδ signaling. Taken together, these results indicate that oxidation of PKCδ is key to the activation of the pathway. The PKCδ/p66Shc/cytochrome c signalo‐some might have evolved to effect site‐directed oxidation of zinc‐finger structures of PKCδ, which harbor the activation centers and the vitamin A binding sites. Our findings define the molecular mechanisms underlying the signaling function of PKCδ in mitochondria.—Acin‐Perez, R., Hoyos, B., Gong, J., Vino‐gradov, V., Fischman, D. A., Leitges, M., Borhan, B., Starkov, A., Manfredi, G., Hammerling, U. Regulation of intermediary metabolism by the PKCδ signa‐losome in mitochondria. FASEB J. 24, 5033–5042 (2010). www.fasebj.org