Editing Calorie restriction (section)

=== Sirtuin-mediated mechanism ===

{{Main|Caloric restriction mimetic}}

Preliminary research indicates that [[sirtuin]]s are activated by fasting and serve as "energy sensors" during [[metabolism]].<ref>{{Cite journal |vauthors=Chang HC, Guarente L |date=March 2014 |title=SIRT1 and other sirtuins in metabolism |journal=Trends in Endocrinology and Metabolism |volume=25 |issue=3 |pages=138–145 |doi=10.1016/j.tem.2013.12.001 |pmc=3943707 |pmid=24388149 |hdl=1721.1/104067}}</ref> Sirtuins, specifically Sir2 (found in yeast) have been implicated in the aging of yeast,<ref name="cshs">{{Cite journal |vauthors=Guarente L |date=2007 |title=Sirtuins in aging and disease |journal=Cold Spring Harbor Symposia on Quantitative Biology |volume=72 |pages=483–488 |doi=10.1101/sqb.2007.72.024 |pmid=18419308 |doi-access=free}}</ref> and are a class of [[Conserved sequence|highly conserved]], NAD<sup>+</sup>-dependent [[histone deacetylase]] [[enzyme]]s.<ref name="Lin 12–16">{{Cite journal |vauthors=Lin SJ, Ford E, [[Marcia Haigis|Haigis M]], Liszt G, Guarente L |date=January 2004 |title=Calorie restriction extends yeast life span by lowering the level of NADH |journal=Genes & Development |volume=18 |issue=1 |pages=12–16 |doi=10.1101/gad.1164804 |pmc=314267 |pmid=14724176}}</ref> Sir2 homologs have been identified in a wide range of organisms from bacteria to humans.<ref name=cshs/><ref name="Kaeberlein, M. 1999">{{Cite journal |vauthors=Kaeberlein M, McVey M, Guarente L |date=October 1999 |title=The SIR2/3/4 complex and SIR2 alone promote longevity in Saccharomyces cerevisiae by two different mechanisms |journal=Genes & Development |volume=13 |issue=19 |pages=2570–2580 |doi=10.1101/gad.13.19.2570 |pmc=317077 |pmid=10521401}}</ref>