title: Age-related changes in the mitochondrial proteome of the fungus Podospora anserina analyzed by 2D-DIGE and LC-MS/MS.
abstract: Many questions concerning the molecular processes during biological aging remain unanswered. Since mitochondria are central players in aging, we applied quantitative two-dimensional difference gel electrophoresis (2D-DIGE) coupled to protein identification by mass spectrometry to study the age-dependent changes in the mitochondrial proteome of the fungus Podospora anserina - a well-established aging model. 67 gel spots exhibited significant, but remarkably moderate intensity changes. While typically the observed changes in protein abundance occurred progressively with age, for several proteins a pronounced change was observed at late age, sometimes inverting the trend observed at younger age. The identified proteins were assigned to a wide range of metabolic pathways including several implicated previously in biological aging. An overall decrease for subunits of complexes I and V of oxidative phosphorylation was confirmed by Western blot analysis and blue-native electrophoresis. Changes in several groups of proteins suggested a general increase in protein biosynthesis possibly reflecting a compensatory mechanism for increased quality control-related protein degradation at later age. Age-related augmentation in abundance of proteins involved in biosynthesis, folding, and protein degradation pathways sustain these observations. Furthermore, a significant decrease of two enzymes involved in the degradation of γ-aminobutyrate (GABA) supported its previously suggested involvement in biological aging.
  
  
  CONCLUSIONS
  We have followed the time course of changes in protein abundance during aging of the fungus P. anserina. The observed moderate but significant changes provide insight into the molecular adaptations to biological aging and highlight the metabolic pathways involved, thereby offering new leads for future research.
authors.affiliation: Molecular Bioenergetics Group, Medical School, Cluster of Excellence Frankfurt Macromolecular Complexes, Centre for Membrane Proteomics, Johann Wolfgang Goethe University, 60590 Frankfurt am Main, Germany.
authors.forename: Marthe A
authors.initials: MA
authors.lastname: Chimi
authors.forename: Stefan
authors.initials: S
authors.lastname: Dröse
authors.forename: Ilka
authors.initials: I
authors.lastname: Wittig
authors.forename: Heinrich
authors.initials: H
authors.lastname: Heide
authors.forename: Mirco
authors.initials: M
authors.lastname: Steger
authors.forename: Alexandra
authors.initials: A
authors.lastname: Werner
authors.forename: Andrea
authors.initials: A
authors.lastname: Hamann
authors.forename: Heinz D
authors.initials: HD
authors.lastname: Osiewacz
authors.forename: Ulrich
authors.initials: U
authors.lastname: Brandt
mesh_terms: D002853:Chromatography, Liquid; D005656:Fungal Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D024101:Mitochondrial Proteins / Q000378:metabolism*; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry; D010766:Phosphorylation; D048468:Podospora / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D014357:Trypsin / Q000737:chemistry; D057825:Two-Dimensional Difference Gel Electrophoresis; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D024101:Mitochondrial Proteins; D020543:Proteome; D005680:gamma-Aminobutyric Acid; D014357:Trypsin; D010100:Oxygen
keywords: 2D-DIGE; Aging; Mass spectrometry; Mitochondria; Podospora anserina