Formins and tropomyosins (Tpms) are two central components of the microfilaments. Formins are involved in the nucleation and polymerization of actin filaments, and Tpms form along the actin stress fibers to regulate their dynamics. However, the correlation between formins and Tpms remains unclear. Here, we elucidated the function of distinct formins and their specific regulation to the subcellular‐localization of Tpm isoforms on dorsal stress fibers in human osteosarcoma cells. Knockdown of individual formin isoform led to varied defects in actin stress fiber network, but did not affect the expression level of other formin isoforms and Tpms. Further investigation showed that different formins regulated distinct Tpm isoforms in decorating dorsal stress fibers. Specifically, DAAM1 and FHOD1 restricted the distal end expression of Tpm3.1; INF2 controlled the approximate localization of Tpm4.2; and Dia1 partially modulated the dorsal localization of Tpm1.6. Taken together, these data provide microscopy experimental evidence that different formins restrict the localization of distinct Tpm isoforms on dorsal actin stress fibers.

中文翻译：

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不同的formins限制独特的原肌球蛋白在骨肉瘤细胞的背应力纤维上的定位。

福尔马林和原肌球蛋白（Tpms）是微丝的两个主要组成部分。Formin参与肌动蛋白丝的成核和聚合，并且Tpms沿着肌动蛋白应力纤维形成以调节其动力学。但是，formins和Tpms之间的相关性仍不清楚。在这里，我们阐明了不同的formins的功能及其对TPm亚型在人骨肉瘤细胞背应力纤维上的亚细胞定位的特殊调控。击倒单个甲酸形式导致了肌动蛋白应力纤维网络中的各种缺陷，但并未影响其他形式的甲醛和TPMs的表达水平。进一步的研究表明，在装饰背应力纤维中，不同的formins调节不同的TPm亚型。具体来说，DAAM1和FHOD1限制了Tpm3.1的远端表达。INF2控制着Tpm4.2的近似定位。Dia1部分调节了Tpm1.6的背侧定位。综上所述，这些数据提供了显微镜实验证据，表明不同的formins限制了背肌动蛋白应激纤维上不同TPM异构体的定位。