Protein degradation – an alternative respiratory substrate for stressed plants

• Published in: Trends in plant science 2011-09, Vol.16 (9), p.489-498
• Main Authors: Araújo, Wagner L., Tohge, Takayuki, Ishizaki, Kimitsune, Leaver, Christopher J., Fernie, Alisdair R.
• Format: Article
• Language: English
• Subjects: Amino Acids - metabolism; Autophagy; Biological and medical sciences; Cell Respiration; Chlorophyll - metabolism; Citric Acid Cycle; Electron Transport; Electron-Transferring Flavoproteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; Genes, Plant; Mitochondria - metabolism; Oxidative Stress; Plant Proteins - metabolism; Plants - genetics; Plants - metabolism; Proteasome Endopeptidase Complex - metabolism; Transcription, Genetic; Ubiquitination
• ISSN: 1360-1385; 1878-4372
• DOI: 10.1016/j.tplants.2011.05.008

In cellular circumstances under which carbohydrates are scarce, plants can metabolize proteins and lipids as alternative respiratory substrates. Respiration of protein is less efficient than that of carbohydrate as assessed by the respiratory quotient; however, under certain adverse conditions, it represents an important alternative energy source for the cell. Significant effort has been invested in understanding the regulation of protein degradation in plants. This has included an investigation of how proteins are targeted to the proteosome, and the processes of senescence and autophagy. Here we review these events with particular reference to amino acid catabolism and its role in supporting the tricarboxylic acid cycle and direct electron supply to the ubiquinone pool of the mitochondrial electron transport chain in plants.