The ankyrin-B C-terminal domain determines activity of ankyrin-B/G chimeras in rescue of abnormal inositol 1,4,5-trisphosphate and ryanodine receptor distribution in ankyrin-B (-/-) neonatal cardiomyocytes
The ankyrin-B C-terminal domain determines activity of ankyrin-B/G chimeras in rescue of abnormal inositol 1,4,5-trisphosphate and ryanodine receptor distribution in ankyrin-B (-/-) neonatal cardiomyocytes
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DOI：
10.1074/jbc.m110958200
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发表时间：
2002-03-22
影响因子：
4.8
通讯作者：
Bennett, V
中科院分区：
文献类型：
--
作者：
Mohler, PJ;Gramolini, AO;Bennett, V
锚蛋白是一个密切相关的膜接头蛋白家族，据信其参与将不同的膜蛋白靶向质膜和内质网中的特定结构域。这项研究解决了单个锚蛋白亚型在同一细胞中共表达时如何实现功能特异性的问题。来自锚蛋白-B (-/-) 小鼠的心肌细胞表现出肌醇 1,4,5-三磷酸受体和兰尼碱受体的错误定位以及收缩率降低，这可以通过表达绿色荧光蛋白 (GFP)-锚蛋白-B 而不是 GFP-锚蛋白-G 来挽救。我们开发了包含锚蛋白-B 和锚蛋白-G 三个主要结构域的所有组合的嵌合 GFP 表达构建体，以确定锚蛋白-B 特异性功能需要锚蛋白-B 的哪些结构域。锚蛋白-B 的死亡/C 末端结构域决定了锚蛋白-B/G 嵌合体在心肌细胞中以条纹图案定位的活性，以及恢复兰尼碱和肌醇 1,4,5-三磷酸受体的正常条纹分布以及收缩心肌细胞的正常搏动频率的活性。死亡/C 端结构域内的进一步删除表明，C 端结构域决定锚蛋白-B 活性，而死亡结构域的删除则没有影响。 C 端结构域是锚蛋白异构体之间差异最大的结构域，是编码使锚蛋白能够选择性地将蛋白质靶向不同细胞位点的信号的候选结构域。
Ankyrins are a closely related family of membrane adaptor proteins that are believed to participate in targeting diverse membrane proteins to specialized domains in the plasma membrane and endoplasmic reticulum. This study addresses the question of how individual ankyrin isoforms achieve functional specificity when co-expressed in the same cell. Cardiomyocytes from ankyrin-B (-/-) mice display mis-localization of inositol 1,4,5-trisphosphate receptors and ryanodine receptors along with reduced contraction rates that can be rescued by expression of green fluorescent protein (GFP)-ankyrin-B but not GFP-ankyrin-G. We developed chimeric GFP expression constructs containing all combinations of the three major domains of ankyrin-B and ankyrin-G to determine which domain(s) of ankyrin-B are required for ankyrin-B-specific functions. The death/C-terminal domain of ankyrin-B determined activity of ankyrin-B/G chimeras in localization in a striated pattern in cardiomyocytes and in restoration of a normal striated distribution of both ryanodine and inositol 1,4,5-trisphosphate receptors as well as normal beat frequency of contracting cardiomyocytes. Further deletions within the death/C-terminal domain demonstrated that the C-terminal domain determines ankyrin-B activity, whereas deletion of the death domain had no effect. C-terminal domains are the most divergent between ankyrin isoforms and are candidates to encode the signal(s) that enable ankyrins to selectively target proteins to diverse cellular sites.