title: Structural and functional analysis of novel human cytochrome C targets in apoptosis.
abstract: Since the first description of apoptosis four decades ago, great efforts have been made to elucidate, both in vivo and in vitro, the molecular mechanisms involved in its regulation. Although the role of cytochrome c during apoptosis is well established, relatively little is known about its participation in signaling pathways in vivo due to its essential role during respiration. To obtain a better understanding of the role of cytochrome c in the onset of apoptosis, we used a proteomic approach based on affinity chromatography with cytochrome c as bait in this study. In this approach, novel cytochrome c interaction partners were identified whose in vivo interaction and cellular localization were facilitated through bimolecular fluorescence complementation. Modeling of the complex interface between cytochrome c and its counterparts indicated the involvement of the surface surrounding the heme crevice of cytochrome c, in agreement with the vast majority of known redox adducts of cytochrome c. However, in contrast to the high turnover rate of the mitochondrial cytochrome c redox adducts, those occurring under apoptosis led to the formation of stable nucleo-cytoplasmic ensembles, as inferred mainly from surface plasmon resonance and nuclear magnetic resonance measurements, which permitted us to corroborate the formation of such complexes in vitro. The results obtained suggest that human cytochrome c interacts with pro-survival, anti-apoptotic proteins following its release into the cytoplasm. Thus, cytochrome c may interfere with cell survival pathways and unlock apoptosis in order to prevent the spatial and temporal coexistence of antagonist signals.
authors.affiliation: From the ‡Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain;
authors.forename: Jonathan
authors.initials: J
authors.lastname: Martínez-Fábregas
authors.affiliation: From the ‡Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain;
authors.forename: Irene
authors.initials: I
authors.lastname: Díaz-Moreno
authors.affiliation: From the ‡Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain;
authors.forename: Katiuska
authors.initials: K
authors.lastname: González-Arzola
authors.affiliation: §Institut für Biochemie, Universität des Saarlandes, Campus B2.2, D-66123 Saarbrücken, Germany;
authors.forename: Simon
authors.initials: S
authors.lastname: Janocha
authors.affiliation: From the ‡Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain;
authors.forename: José A
authors.initials: JA
authors.lastname: Navarro
authors.affiliation: From the ‡Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain;
authors.forename: Manuel
authors.initials: M
authors.lastname: Hervás
authors.affiliation: §Institut für Biochemie, Universität des Saarlandes, Campus B2.2, D-66123 Saarbrücken, Germany;
authors.forename: Rita
authors.initials: R
authors.lastname: Bernhardt
authors.affiliation: ¶Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint-Unit IQFR-CSIC-BIFI, Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Zaragoza, Spain, and Fundacion ARAID, Government of Aragon, Zaragoza, Spain.
authors.forename: Adrián
authors.initials: A
authors.lastname: Velázquez-Campoy
authors.affiliation: From the ‡Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain;
authors.forename: Antonio
authors.initials: A
authors.lastname: Díaz-Quintana
authors.affiliation: From the ‡Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain; marosa@us.es.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: De la Rosa
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival / Q000235:genetics; D018360:Crystallography, X-Ray; D045304:Cytochromes c / Q000096:biosynthesis* / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D015398:Signal Transduction / Q000235:genetics
chemical_list: D045304:Cytochromes c; D053148:Caspase 3