6n1o
From Proteopedia
Oxidized rat cytochrome c mutant (S47E)
Structural highlights
Function[CYC_RAT] Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain. Plays a role in apoptosis. Suppression of the anti-apoptotic members or activation of the pro-apoptotic members of the Bcl-2 family leads to altered mitochondrial membrane permeability resulting in release of cytochrome c into the cytosol. Binding of cytochrome c to Apaf-1 triggers the activation of caspase-9, which then accelerates apoptosis by activating other caspases (By similarity). Publication Abstract from PubMedCytochrome c (Cytc) is a multifunctional protein that operates as an electron carrier in the mitochondrial electron transport chain and plays a key role in apoptosis. We have previously shown that tissue-specific phosphorylations of Cytc in the heart, liver, and kidney play an important role in the regulation of cellular respiration and cell death. Here, we report that Cytc purified from mammalian brain is phosphorylated on S47 and that this phosphorylation is lost during ischemia. We have characterized the functional effects in vitro using phosphorylated Cytc purified from pig brain tissue and a recombinant phosphomimetic mutant (S47E). We crystallized S47E phosphomimetic Cytc at 1.55 A and suggest that it spatially matches S47-phosphorylated Cytc, making it a good model system. Both S47-phosphorylated and phosphomimetic Cytc showed a lower oxygen consumption rate in reaction with isolated Cytc oxidase, which we propose maintains intermediate mitochondrial membrane potentials under physiologic conditions, thus minimizing production of reactive oxygen species. S47-phosphorylated and phosphomimetic Cytc showed lower caspase-3 activity. Furthermore, phosphomimetic Cytc had decreased cardiolipin peroxidase activity and is more stable in the presence of H2O2. Our data suggest that S47 phosphorylation of Cytc is tissue protective and promotes cell survival in the brain.-Kalpage, H. A., Vaishnav, A., Liu, J., Varughese, A., Wan, J., Turner, A. A., Ji, Q., Zurek, M. P., Kapralov, A. A., Kagan, V. E., Brunzelle, J. S., Recanati, M.-A., Grossman, L. I., Sanderson, T. H., Lee, I., Salomon, A. R., Edwards, B. F. P, Huttemann, M. Serine-47 phosphorylation of cytochrome c in the mammalian brain regulates cytochrome c oxidase and caspase-3 activity. Serine-47 phosphorylation of cytochrome c in the mammalian brain regulates cytochrome c oxidase and caspase-3 activity.,Kalpage HA, Vaishnav A, Liu J, Varughese A, Wan J, Turner AA, Ji Q, Zurek MP, Kapralov AA, Kagan VE, Brunzelle JS, Recanati MA, Grossman LI, Sanderson TH, Lee I, Salomon AR, Edwards BFP, Huttemann M FASEB J. 2019 Sep 28:fj201901120R. doi: 10.1096/fj.201901120R. PMID:31570002[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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