Expression and subcellular localization of mammalian formin Fhod3 in the embryonic and adult heart.
Expression and subcellular localization of mammalian formin Fhod3 in the embryonic and adult heart.
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DOI：
10.1371/journal.pone.0034765
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Sumimoto H
中科院分区：
文献类型：
--
作者：
Kan-o M;Takeya R;Taniguchi K;Tanoue Y;Tominaga R;Sumimoto H
福尔明家族蛋白通过 FH2 结构域在肌动蛋白丝组装中发挥关键作用。哺乳动物formin Fhod3在心脏中高表达，其在成年心脏中的mRNA含有外显子11、12和25，这些外显子是非肌肉Fhod3亚型所不存在的。在培养的新生儿心肌细胞中，Fhod3 定位于肌节中部，并似乎在其组织中发挥作用，尽管有人认为 Fhod3 在成人心脏中的定位不同。在这里，我们使用三种不同的抗体（每种抗体识别 Fhod3 的不同区域）进行免疫组织化学分析，结果表明，Fhod3 在胚胎和成人心脏的肌节中部定位为两条间隔很近的带。这些带与在肌节中心交联粗肌球蛋白丝的 M 线相邻，但远离形成肌节边界的 Z 线，其定位与在培养的心肌细胞中观察到的定位相同。详细的免疫组织化学和免疫电子显微镜分析表明，Fhod3 并不定位于细肌动蛋白丝的尖端，而是定位于更外围的区域，其中细丝与粗肌球蛋白丝重叠。我们还证明，小鼠的胚胎心脏特异性表达包含三个替代外显子的 Fhod3 mRNA 同种型，并且 Fhod3 在肌节中的特征定位不需要外显子 25 编码的区域，这与外显子 11 和 12 的重要作用相反。此外，外显子 25 编码区域对于体内和体外的肌动蛋白组织活动似乎都是可有可无的，尽管它是插入的在催化 FH2 结构域中。
The formin family proteins play pivotal roles in actin filament assembly via the FH2 domain. The mammalian formin Fhod3 is highly expressed in the heart, and its mRNA in the adult heart contains exons 11, 12, and 25, which are absent from non-muscle Fhod3 isoforms. In cultured neonatal cardiomyocytes, Fhod3 localizes to the middle of the sarcomere and appears to function in its organization, although it is suggested that Fhod3 localizes differently in the adult heart. Here we show, using immunohistochemical analysis with three different antibodies, each recognizing distinct regions of Fhod3, that Fhod3 localizes as two closely spaced bands in middle of the sarcomere in both embryonic and adult hearts. The bands are adjacent to the M-line that crosslinks thick myosin filaments at the center of a sarcomere but distant from the Z-line that forms the boundary of the sarcomere, which localization is the same as that observed in cultured cardiomyocytes. Detailed immunohistochemical and immuno-electron microscopic analyses reveal that Fhod3 localizes not at the pointed ends of thin actin filaments but to a more peripheral zone, where thin filaments overlap with thick myosin filaments. We also demonstrate that the embryonic heart of mice specifically expresses the Fhod3 mRNA isoform harboring the three alternative exons, and that the characteristic localization of Fhod3 in the sarcomere does not require a region encoded by exon 25, in contrast to an essential role of exons 11 and 12. Furthermore, the exon 25-encoded region appears to be dispensable for actin-organizing activities both in vivo and in vitro, albeit it is inserted in the catalytic FH2 domain.
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DOI：
10.1038/nrm2867
发表时间：
2010-04
期刊：
Nature reviews. Molecular cell biology
影响因子：
--
作者：
通讯作者：
--
影响因子：
2.5
作者：
Kulandavelu, S;Qu, DW;Adamson, SL
通讯作者：
Adamson, SL
影响因子：
3.7
作者：
GOSHIMA, K
通讯作者：
GOSHIMA, K
影响因子：
11.8
作者：
Bai, Jianwu;Hartwig, John H.;Perrimon, Norbert
通讯作者：
Perrimon, Norbert
影响因子：
7.3
作者：
Littlefield RS;Fowler VM
通讯作者：
Fowler VM