A Heterozygous Mutation in the Third Transmembrane Domain Causes a Dominant-Negative Effect on Signalling Capability of the MC4R
A Heterozygous Mutation in the Third Transmembrane Domain Causes a Dominant-Negative Effect on Signalling Capability of the MC4R
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第三跨膜结构域的杂合突变对 MC4R 信号传导能力产生显性负效应
DOI：
10.1159/000138251
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发表时间：
2008
期刊：
影响因子：
3.6
通讯作者：
Biebermann H
中科院分区：
文献类型：
--
作者：
Tarnow P;Rediger A;Brumm H;Ambrugger P;Rettenbacher E;Widhalm K;Hinney A;Kleinau G;Schaefer M;Hebebrand J;Krause G;Grüters A;Biebermann H
背景：MC 4 R杂合突变是单基因肥胖最常见的原因。对于大多数MC 4 R突变，基因剂量效应似乎是潜在的机制。然而，一个杂合子MC 4 R突变的显性负效应最近被确定，指向MC 4 R inactivation.Methods的额外机制：完全丧失功能的突变（Ser 136 Phe），确定在一个队列的肥胖奥地利患者，其特征在于细胞表面表达，信号转导和配体结合特性。共转染研究测试了显性负效应。通过夹心ELISA和荧光共振能量转移（FRET）方法研究二聚化。根据β2肾上腺素能受体的晶体结构，用同源受体模型研究了Ser 136的潜在分子内相互作用。夹心ELISA和FRET方法证明了突变体和野生型受体的二聚化。受体模型揭示了跨膜螺旋3（TMH 3）上的Ser 136对于在TMH 2、TMH 3和TMH 7之间建立H键的基本功能。突变Ser 136 Phe最有可能破坏这个网络，并导致一个不称职的螺旋-螺旋排列在突变receptor.Conclusion：鉴定显性负MC 4 R突变是重要的，以充分了解受体功能，并确定受体区域参与MC 4 R二聚体激活。
Background:Heterozygous MC4R mutation is the most frequent cause of monogenic obesity. For most MC4R mutations a gene dosage effect seems to be the underlying mechanism. However, a dominant negative effect of a heterozygous MC4R mutation was recently identified, pointing to an additional mechanism of MC4R inactivation.Methods:The complete loss-of-function mutation (Ser136Phe), identified in a cohort of obese Austrian patients, was characterized for cell surface expression, signal transduction and ligand binding properties. Co-transfection studies tested for a dominant negative effect. Dimerization was investigated by a sandwich ELISA and by fluorescence resonance energy transfer (FRET) approach. Potential intramolecular interactions of Ser136 were studied by homologous receptor modelling based on the crystal structure of the β2-adrenergic receptor.Results:The Ser136Phe mutation showed a dominant negative effect. The sandwich ELISA and FRET approach demonstrated dimerization of mutant and wild type receptor. Receptor modelling revealed an essential function of Ser136 at transmembrane helix 3 (TMH3) for establishing H-bonds between TMH2, TMH3, and TMH7. The mutation Ser136Phe most likely disrupts this network and leads to an incompetent helix-helix arrangement in the mutated receptor.Conclusion:Identification of dominant negative MC4R mutations is important to fully understand receptor function and to determine receptor regions that are involved in MC4R dimer activation.
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视觉中的 G 蛋白偶联受体视紫红质。
DOI：
--
发表时间：
2007
期刊：
Farumashia (in press)
影响因子：
--
作者：
Takahashi;R.;et al.;H.Tsukamoto
通讯作者：
H.Tsukamoto
影响因子：
29
作者：
Biebermann, H;Castañeda, TR;Krude, H
通讯作者：
Krude, H
DOI：
10.1073/pnas.0608022103
发表时间：
2006-10-31
影响因子：
11.1
作者：
Salom, David;Lodowski, David T.;Palczewski, Krzysztof
通讯作者：
Palczewski, Krzysztof
DOI：
10.1016/s0021-9258(18)82452-8
发表时间：
1993-07
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
I. Gantz;Hiroto Miwa;Y. Konda;Y. Shimoto;T. Tashiro;S. Watson;J. Delvalle;Tadataka Yamada
通讯作者：
I. Gantz;Hiroto Miwa;Y. Konda;Y. Shimoto;T. Tashiro;S. Watson;J. Delvalle;Tadataka Yamada
影响因子：
7.7
作者：
Gu, W;Tu, ZM;Allison, DB
通讯作者：
Allison, DB