Rapsyn interacts with the muscle acetylcholine receptor via alpha-helical domains in the alpha, beta, and epsilon subunit intracellular loops.
Rapsyn interacts with the muscle acetylcholine receptor via alpha-helical domains in the alpha, beta, and epsilon subunit intracellular loops.
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DOI：
10.1016/j.neuroscience.2009.05.057
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发表时间：
2009-09-29
期刊：
影响因子：
3.3
通讯作者：
Ferns, M.
中科院分区：
文献类型：
--
作者：
Lee, Y.;Rudell, J.;Ferns, M.
在发育中的脊椎动物神经肌肉接头处，乙酰胆碱受体以高密度聚集在突触后肌肉膜上。受体定位由运动神经元衍生因子聚集蛋白调节，并且需要称为rapsyn的细胞内支架蛋白。然而，目前还不清楚rapsyn在哪里与乙酰胆碱受体结合，以及它们之间的相互作用是如何调节的。在这项研究中，我们确定了rapsyn的结合位点上的乙酰胆碱受体使用嵌合结构的CD 4的细胞内结构域被取代的主要细胞内环的每个小鼠乙酰胆碱受体亚基。当在异源细胞中表达时，我们发现rapsyn聚集并在细胞内锚定CD 4- α，β和ε亚基环，但不锚定CD 4-δ环。Rapsyn介导的聚集和锚定对于β环最高，其次是ε，然后是α，表明rapsyn以不同的亲和力与环相互作用。此外，通过在β亚基细胞内环内进行缺失，我们表明rapsyn与α-螺旋区域相互作用，α-螺旋区域是亚基环C-末端部分的二级结构基序。当在肌肉细胞中表达时，rapsyn与CD 4-α螺旋区嵌合体一起免疫共沉淀，不依赖于聚集蛋白信号传导。总之，这些发现表明rapsyn通过α，β和ε亚基之间保守的α-螺旋结构基序与乙酰胆碱受体相互作用。结合在这个网站可能介导的关键rapsyn相互作用参与定位乙酰胆碱受体在神经肌肉接头。
At the developing vertebrate neuromuscular junction, the acetylcholine receptor becomes aggregated at high density in the postsynaptic muscle membrane. Receptor localization is regulated by the motoneuron-derived factor, agrin, and requires an intracellular, scaffolding protein called rapsyn. However, it remains unclear where rapsyn binds on the acetylcholine receptor and how their interaction is regulated. In this study, we identified rapsyn’s binding site on the acetylcholine receptor using chimeric constructs where the intracellular domain of CD4 was substituted for the major intracellular loop of each mouse acetylcholine receptor subunit. When expressed in heterologous cells, we found that rapsyn clustered and cytoskeletally anchored CD4- α, β and ε subunit loops but not CD4-δ loop. Rapsyn-mediated clustering and anchoring was highest for β loop, followed by ε and then α, suggesting that rapsyn interacts with the loops with different affinities. Moreover, by making deletions within the β subunit intracellular loop, we show that rapsyn interacts with the α-helical region, a secondary structural motif present in the C-terminal portion of the subunit loops. When expressed in muscle cells, rapsyn co-immunoprecipitated together with a CD4-α helical region chimera, independent of agrin signaling. Together, these findings demonstrate that rapsyn interacts with the acetylcholine receptor via an α-helical structural motif conserved between the α, β and ε subunits. Binding at this site likely mediates the critical rapsyn interaction involved in localizing the acetylcholine receptor at the neuromuscular junction.
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影响因子：
56.9
作者：
Beeson, David;Higuchi, Osamu;Yamanashi, Yuji
通讯作者：
Yamanashi, Yuji
影响因子：
25
作者：
Finn, AJ;Feng, GP;Pendergast, AM
通讯作者：
Pendergast, AM
DOI：
10.1073/pnas.82.23.8270
发表时间：
1985-01-01
影响因子：
11.1
作者：
BURDEN, SJ
通讯作者：
BURDEN, SJ
影响因子：
4.7
作者：
Kneussel, M;Hermann, A;Betz, H
通讯作者：
Betz, H
DOI：
10.1073/pnas.78.8.5230
发表时间：
1981-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
FROEHNER, SC;GULBRANDSEN, V;COHEN, JB
通讯作者：
COHEN, JB