Chemical activation of Sir2-dependent silencing by relief of nicotinamide inhibition
Chemical activation of Sir2-dependent silencing by relief of nicotinamide inhibition
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DOI：
10.1016/j.molcel.2004.12.032
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发表时间：
2005-02-18
期刊：
影响因子：
16
通讯作者：
Willis, IM
中科院分区：
文献类型：
--
作者：
Sauve, AA;Moir, RD;Willis, IM
Sir2是烟酰胺腺嘌呤二核苷酸（NAD（+））依赖性蛋白脱乙酰酶，参与基因沉默和长寿。细胞应激会影响Sir2的活性，但Sir2的调节机制仍有争议。烟酰胺已被提议作为生理调节剂，其通过共价反应中间体的化学逆转来抑制Sir2脱乙酰酶活性。我们证明了一种化学策略，以激活Sir2依赖的转录沉默和目前的证据表明，内源性水平的烟酰胺限制Sir2活性在野生型（wt）酵母细胞。烟酰胺对Sir2的抑制作用在体外被异烟酰胺拮抗，这导致Sir2去乙酰化活性增加。异烟酰胺还显著增加野生型菌株和缺乏关键NAD（+）补救途径酶（PNC 1和NPT 1）的菌株中Sir 2调节基因座处的转录沉默。因此，烟酰胺拮抗剂在体外和体内是Sir2激动剂。
Sir2 is a nicotinamide adenine dinucleotide (NAD(+)) dependent protein deacetylase involved in gene silencing and longevity. Cellular stresses affect Sir2 activity, but the mechanisms of Sir2 regulation are debated. Nicotinamide has been proposed as a physiological regulator that inhibits Sir2 deacetylase activity by chemical reversal of a covalent reaction intermediate. We demonstrate a chemical strategy to activate Sir2-dependent transcriptional silencing and present evidence that the endogenous level of nicotinamide limits Sir2 activity in wild-type (wt) yeast cells. Nicotinamide inhibition of Sir2 is antagonized in vitro by isonicotinamide, which causes an increase in Sir2 deacetylation activity. Isonicotinamide also substantially increases transcriptional silencing at Sir2-regulated loci in wt strains and in strains lacking key NAD(+) salvage pathway enzymes (PNC1 and NPT1). Thus, a nicotinamide antagonist is a Sir2 agonist in vitro and in vivo.