연사 : 이병천교수 (고려대학교 생명공학부)
연제 : Methionine impact on living organisms : Lessons from redox biology and aging
일시 : 2015년 5월 1일 (금) 오후 4시
장소 : 하나과학관 A동 101호
초청교수 : 김익영교수
Abstract
Methionine is a key metabolite at the junction of protein synthesis and sulfur metabolism. In a redox biology, Methionine is highly susceptible to oxidation by reactive oxygen species, resulting in a mixture of two diastereomers, methionine-S-sulfoxide and methionine-R-sulfoxide, that is associated with incidence of various diseases. To counteract methionine oxidation, organisms evolved to have two independent Msr enzymes, MsrA and MsrB. MsrA reduces both free amino acid and protein-based forms of methionine-S-sulfoxide, whereas MsrB reduces protein-based forms of methionine-R-sulfoxide in stereospecific manner. In mammals, MsrB1 is a selenoprotein and regulates mammalian actin assembly via stereoselective methionine oxidation and reduction. This regulation is necessary for macrophage immune function during cellular activation. In an aging biology, Methionine is a specific nutrient that control lifespan extension by its restricted use, mimicking the effect by calorie restriction. Overexpression of InRDN or Tsc2 inhibits lifespan extension by Met restriction, suggesting the role of TOR signaling in the Met control of longevity.