Department of Biology/Chemistry, Division of Animal Physiology, University of Osnabrück, 49076, Osnabrück, Germany.
Pflugers Arch. 2017 Nov;469(11):1433-1442. doi: 10.1007/s00424-017-2024-9. Epub 2017 Jul 8.
In the present study, we describe the detection and analysis of a novel type of sugar transporter in mammalian spermatozoa. This transporter belongs to the SLC45 family for which two features are remarkable and distinguish it from other known families of sugar transporters. Firstly, SLC45 transporters recognise not only the monosaccharides glucose or fructose but also the disaccharide sucrose as a substrate. Secondly, the uptake of sugars is coupled to a proton gradient. Uptake experiments using radioactively labelled sucrose indicated a functional transporter of the SLC45 family in bull spermatozoa. Real-time PCR as well as Western blots demonstrated the occurrence of the SLC45 member A4 in mouse testis and sperms. Furthermore, immunocytochemical analysis of mouse tissues revealed that the signal of SLC45A4 was mainly located in the principle piece of spermatozoa. We postulate that the SLC45A4 transporter plays an important role in nutrition of spermatozoa during their maturation in the epididymis. Moreover, we suggest that knowledge about the presence of the SLC45A4 may be useful also for the methodical improvement of cryopreservation of mammalian spermatozoa.
在本研究中，我们描述了在哺乳动物精子中新型糖转运蛋白的检测和分析。这种转运蛋白属于 SLC45 家族，该家族有两个显著特征使其有别于其他已知的糖转运蛋白家族。首先，SLC45 转运蛋白不仅能识别单糖葡萄糖或果糖，还能识别二糖蔗糖作为底物。其次，糖的摄取与质子梯度相偶联。使用放射性标记的蔗糖进行摄取实验表明，牛精子中存在 SLC45 家族的功能性转运蛋白。实时 PCR 和 Western blot 表明 SLC45 成员 A4 存在于小鼠睾丸和精子中。此外，对小鼠组织的免疫细胞化学分析表明，SLC45A4 的信号主要位于精子的主段。我们推测，SLC45A4 转运蛋白在精子在附睾中成熟过程中的营养中起着重要作用。此外，我们认为了解 SLC45A4 的存在可能对哺乳动物精子的冷冻保存方法的改进也有帮助。
