title: Signalling through RHEB-1 mediates intermittent fasting-induced longevity in C. elegans.
abstract: Dietary restriction is the most effective and reproducible intervention to extend lifespan in divergent species. In mammals, two regimens of dietary restriction, intermittent fasting (IF) and chronic caloric restriction, have proven to extend lifespan and reduce the incidence of age-related disorders. An important characteristic of IF is that it can increase lifespan even when there is little or no overall decrease in calorie intake. The molecular mechanisms underlying IF-induced longevity, however, remain largely unknown. Here we establish an IF regimen that effectively extends the lifespan of Caenorhabditis elegans, and show that the low molecular weight GTPase RHEB-1 has a dual role in lifespan regulation; RHEB-1 is required for the IF-induced longevity, whereas inhibition of RHEB-1 mimics the caloric-restriction effects. RHEB-1 exerts its effects in part by the insulin/insulin growth factor (IGF)-like signalling effector DAF-16 in IF. Our analyses demonstrate that most fasting-induced upregulated genes require RHEB-1 function for their induction, and that RHEB-1 and TOR signalling are required for the fasting-induced downregulation of an insulin-like peptide, INS-7. These findings identify the essential role of signalling by RHEB-1 in IF-induced longevity and gene expression changes, and suggest a molecular link between the IF-induced longevity and the insulin/IGF-like signalling pathway.
authors.affiliation: Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Sakiko
authors.initials: S
authors.lastname: Honjoh
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masaharu
authors.initials: M
authors.lastname: Uno
authors.forename: Eisuke
authors.initials: E
authors.lastname: Nishida
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D031204:Caloric Restriction; D005215:Fasting / Q000502:physiology*; D051858:Forkhead Transcription Factors; D005786:Gene Expression Regulation; D007328:Insulin / Q000378:metabolism; D008136:Longevity / Q000235:genetics / Q000502:physiology*; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D036361:Peptide Hormones / Q000378:metabolism; D000076205:Ras Homolog Enriched in Brain Protein; D015398:Signal Transduction; D013002:Somatomedins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D051858:Forkhead Transcription Factors; C525653:Ins-7 protein, C elegans; D007328:Insulin; D036361:Peptide Hormones; C539143:RHEB-1 protein, C elegans; D000076205:Ras Homolog Enriched in Brain Protein; D013002:Somatomedins; D014157:Transcription Factors; C108831:daf-16 protein, C elegans; D020559:Monomeric GTP-Binding Proteins