RAI14 (retinoic acid induced protein 14) is an F-actin regulator: Lesson from the testis.
RAI14 (retinoic acid induced protein 14) is an F-actin regulator: Lesson from the testis.
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DOI：
10.4161/spmg.24824
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发表时间：
2013-04-01
期刊：
影响因子：
--
通讯作者：
Cheng CY
中科院分区：
文献类型：
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作者：
Qian X;Mruk DD;Cheng YH;Cheng CY
RAI 14（retinoic acid induced protein 14，维甲酸诱导蛋白14）是最早在肝脏中发现的一种肌动蛋白结合蛋白。在睾丸中，RAI 14由生精上皮中的支持细胞和生殖细胞表达。除了与睾丸中的肌动蛋白结合外，RAI 14也是一种palladin的结合蛋白，palladin是一种肌动蛋白交联和捆绑蛋白。最近的一份报告显示，RAI 14显示阶段特异性和时空表达在ES [外质特化，睾丸特异性丝状（F）肌动蛋白丰富的粘附连接]在成年大鼠睾丸生精上皮细胞在精子发生的上皮周期，说明其可能参与在ES的F-肌动蛋白组织。RAI 14在体外支持细胞和体内睾丸细胞中被RNAi敲除的功能研究已经说明了其在赋予ES处肌动蛋白丝束的完整性、在体外扰乱支持细胞紧密连接（TJ）-外周屏障功能以及在体内精子细胞极性和粘附中的作用，从而调节精子细胞在精子形成时的运输。在此，我们批判性地评估了这些早期的发现，并提供了一个可能的假设模型，基于RAI 14在ES中的功能作用，以及RAI 14如何与睾丸中的palladin和其他肌动蛋白调节蛋白一起调节精子发生过程中（1）精子细胞和（2）前细线期精母细胞分别穿过生精上皮和血睾屏障（BTB）的转运。这个模型应该作为一个框架，功能实验可以设计，以更好地了解RAI 14和其他肌动蛋白结合和调节蛋白在睾丸的生物学。
RAI14 (retinoic acid induced protein 14) is an actin-binding protein first identified in the liver. In the testis, RAI14 is expressed by both Sertoli and germ cells in the seminiferous epithelium. Besides binding to actin in the testis, RAI14 is also a binding protein for palladin, an actin cross-linking and bundling protein. A recent report has shown that RAI14 displays stage-specific and spatiotemporal expression at the ES [ectoplasmic specialization, a testis-specific filamentous (F)-actin-rich adherens junction] in the seminiferous epithelium of adult rat testes during the epithelial cycle of spermatogenesis, illustrating its likely involvement in F-actin organization at the ES. Functional studies in which RAI14 was knocked down by RNAi in Sertoli cells in vitro and also in testicular cells in vivo have illustrated its role in conferring the integrity of actin filament bundles at the ES, perturbing the Sertoli cell tight junction (TJ)-pemeability barrier function in vitro, and also spermatid polarity and adhesion in vivo, thereby regulating spermatid transport at spermiation. Herein, we critically evaluate these earlier findings and also provide a likely hypothetic model based on the functional role of RAI14 at the ES, and how RAI14 is working with palladin and other actin regulatory proteins in the testis to regulate the transport of (1) spermatids and (2) preleptotene spermatocytes across the seminiferous epithelium and the blood-testis barrier (BTB), respectively, during spermatogenesis. This model should serve as a framework upon which functional experiments can be designed to better understand the biology of RAI14 and other actin-binding and regulatory proteins in the testis.