Impaired multimerization of human adiponectin mutants associated with diabetes - Molecular structure and multimer formation of adiponectin
Impaired multimerization of human adiponectin mutants associated with diabetes - Molecular structure and multimer formation of adiponectin
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DOI：
10.1074/jbc.m300365200
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发表时间：
2003-10-10
影响因子：
4.8
通讯作者：
Kadowaki, T
中科院分区：
文献类型：
--
作者：
Waki, H;Yamauchi, T;Kadowaki, T
脂联素是一种脂肪细胞来源的激素，已被证明在调节糖脂代谢中发挥重要作用。已有8种脂联素基因突变被报道，其中一些与糖尿病和低脂联素血症显著相关，但脂联素突变体导致血浆水平降低和作用减弱的分子机制尚不清楚。脂联素在结构上属于补体1Q家族，并已知形成一种特有的同源多聚体。在此，我们证明了在非还原和非热变性条件下的简单的SDS-PAGE可以清楚地分离脂联素的多聚体种类。人或小鼠血清中的脂联素和在NIH-3T3或大肠杆菌中表达的脂联素形成了从三聚体到高分子量(HMW)的广泛的多聚体。形成大于三聚体的多聚体需要通过氨基末端半胱氨酸的二硫键。氨基端的Cys-Ser突变不能形成大于三聚体的多聚体，从而消除了脂联素对肝细胞中AMP激活的蛋白激酶途径的影响。在人类脂联素突变中，与糖尿病和低脂联素血症相关的G84R和G90S突变不形成HMW多聚体。与低脂联素血症相关的R112C和I164T突变体没有组装成三聚体，导致细胞分泌受损。这些数据表明，多聚体受损和/或随之而来的分泌受损是具有这些突变的受试者糖尿病表型或低脂联素血症的原因之一。总之，在解释健康和各种疾病状态的血浆脂联素水平时，不仅要考虑总浓度，还要考虑多聚体分布。
Adiponectin is an adipocyte-derived hormone, which has been shown to play important roles in the regulation of glucose and lipid metabolism. Eight mutations in human adiponectin have been reported, some of which were significantly related to diabetes and hypoadiponectinemia, but the molecular mechanisms of decreased plasma levels and impaired action of adiponectin mutants were not clarified. Adiponectin structurally belongs to the complement 1q family and is known to form a characteristic homomultimer. Herein, we demonstrated that simple SDS-PAGE under non-reducing and non-heat-denaturing conditions clearly separates multimer species of adiponectin. Adiponectin in human or mouse serum and adiponectin expressed in NIH-3T3 or Escherichia coli formed a wide range of multimers from trimers to high molecular weight (HMW) multimers. A disulfide bond through an amino-terminal cysteine was required for the formation of multimers larger than a trimer. An amino-terminal Cys-Ser mutation, which could not form multimers larger than a trimer, abrogated the effect of adiponectin on the AMP-activated protein kinase pathway in hepatocytes. Among human adiponectin mutations, G84R and G90S mutants, which are associated with diabetes and hypoadiponectinemia, did not form HMW multimers. R112C and I164T mutants, which are associated with hypoadiponectinemia, did not assemble into trimers, resulting in impaired secretion from the cell. These data suggested impaired multimerization and/or the consequent impaired secretion to be among the causes of a diabetic phenotype or hypoadiponectinemia in subjects having these mutations. In conclusion, not only total concentrations, but also multimer distribution should always be considered in the interpretation of plasma adiponectin levels in health as well as various disease states.