title: Increased Protein Stability and Decreased Protein Turnover in the Caenorhabditis elegans Ins/IGF-1 daf-2 Mutant.
abstract: In Caenorhabditis elegans, cellular proteostasis is likely essential for longevity. Autophagy has been shown to be essential for lifespan extension of daf-2 insulin/IGF mutants. Therefore, it can be hypothesized that daf-2 mutants achieve this phenotype by increasing protein turnover. However, such a mechanism would exert a substantial energy cost. By using classical35S pulse-chase labeling, we observed that protein synthesis and degradation rates are decreased in young adults of the daf-2 insulin/IGF mutants. Although reduction of protein turnover may be energetically favorable, it may lead to accumulation and aggregation of damaged proteins. As this has been shown not to be the case in daf-2 mutants, another mechanism must exist to maintain proteostasis in this strain. We observed that proteins isolated from daf-2 mutants are more soluble in acidic conditions due to increased levels of trehalose. This suggests that trehalose may decrease the potential for protein aggregation and increases proteostasis in the daf-2 mutants. We postulate that daf-2 mutants save energy by decreasing protein turnover rates and instead stabilize their proteome by trehalose.
authors: Laboratory for Aging Physiology and Molecular Evolution, Department of Biology, Ghent University, Belgium.|Laboratory for Functional Genomics and Proteomics, Department of Biology, KU Leuven, Belgium.
authors: Geert
authors: G
authors: Depuydt
authors: Laboratory for Aging Physiology and Molecular Evolution, Department of Biology, Ghent University, Belgium.
authors: Nilesh
authors: N
authors: Shanmugam
authors: Laboratory for Aging Physiology and Molecular Evolution, Department of Biology, Ghent University, Belgium.
authors: Madina
authors: M
authors: Rasulova
authors: Laboratory for Aging Physiology and Molecular Evolution, Department of Biology, Ghent University, Belgium.
authors: Ineke
authors: I
authors: Dhondt
authors: Laboratory for Aging Physiology and Molecular Evolution, Department of Biology, Ghent University, Belgium. Bart.Braeckman@UGent.be.
authors: Bart P
authors: BP
authors: Braeckman
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005978:Glutathione / Q000378:metabolism; D008136:Longevity / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D055550:Protein Stability; D014199:Trehalose / Q000378:metabolism
chemical_list: D000596:Amino Acids; D029742:Caenorhabditis elegans Proteins; D014199:Trehalose; D005978:Glutathione
keywords: 
  Caenorhabditis
  ; Protein metabolism; Radiolabeling.; Trehalose