Li Nan, Wong Chris Kc, Cheng C Yan
The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York 10065, USA.
Department of Biology, Hong Kong Baptist University, Hong Kong, China.
Asian J Androl. 2016 Sep-Oct;18(5):716-22. doi: 10.4103/1008-682X.166583.
Plastins are a family of actin binding proteins (ABPs) known to cross-link actin microfilaments in mammalian cells, creating actin microfilament bundles necessary to confer cell polarity and cell shape. Plastins also support cell movement in response to changes in environment, involved in cell/tissue growth and development. They also confer plasticity to cells and tissues in response to infection or other pathological conditions (e.g., inflammation). In the testis, the cell-cell anchoring junction unique to the testis that is found at the Sertoli cell-cell interface at the blood-testis barrier (BTB) and at the Sertoli-spermatid (e.g., 8-19 spermatids in the rat testis) is the basal and the apical ectoplasmic specialization (ES), respectively. The ES is an F-actin-rich anchoring junction constituted most notably by actin microfilament bundles. A recent report using RNAi that specifically knocks down plastin 3 has yielded some insightful information regarding the mechanism by which plastin 3 regulates the status of actin microfilament bundles at the ES via its intrinsic actin filament bundling activity. Herein, we provide a brief review on the role of plastins in the testis in light of this report, which together with recent findings in the field, we propose a likely model by which plastins regulate ES function during the epithelial cycle of spermatogenesis via their intrinsic activity on actin microfilament organization in the rat testis.
丝束肌动蛋白是一类肌动蛋白结合蛋白（ABP），已知其可在哺乳动物细胞中交联肌动蛋白微丝，形成赋予细胞极性和细胞形状所必需的肌动蛋白微丝束。丝束肌动蛋白还支持细胞对环境变化做出反应而进行移动，参与细胞/组织的生长和发育。它们还能使细胞和组织在受到感染或其他病理状况（如炎症）时具有可塑性。在睾丸中，在血睾屏障（BTB）处的支持细胞-支持细胞界面以及支持细胞-精子细胞（如大鼠睾丸中的8-19个精子细胞）处发现的睾丸特有的细胞-细胞锚定连接分别是基底外质特化（ES）和顶端外质特化。ES是一种富含F-肌动蛋白的锚定连接，最显著的是由肌动蛋白微丝束构成。最近一项使用RNA干扰特异性敲低丝束肌动蛋白3的报告，得出了一些关于丝束肌动蛋白3通过其内在的肌动蛋白丝束集活性调节ES处肌动蛋白微丝束状态机制的有见地的信息。在此，鉴于该报告以及该领域的最新发现，我们对丝束肌动蛋白在睾丸中的作用进行简要综述，并提出一个可能的模型，即丝束肌动蛋白通过其对大鼠睾丸中肌动蛋白微丝组织的内在活性，在精子发生上皮周期中调节ES功能。
