Heid Hans, Figge Ulrike, Winter Stefanie, Kuhn Caecilia, Zimbelmann Ralf, Franke Werner
Division of Cell Biology, German Cancer Research Center, D-69120, Heidelberg, Germany.
Exp Cell Res. 2002 Oct 1;279(2):177-87. doi: 10.1006/excr.2002.5603.
The calyx is a large cytoskeletal component of the perinuclear theca of the mammalian sperm head, displaying remarkable morphological interspecies differences, which is biochemically characterized by resistance to high ionic strength and detergents and by a special protein composition, including the basic proteins calicin, cylicin I and II, and two major actin-capping proteins. In our calyx preparations from bull spermatozoa we have noted two major acidic components which upon partial amino acid sequencing have been identified as novel members of the subfamily of actin-related proteins (Arps). Antibodies raised against the corresponding human proteins, termed Arp-T1 and Arp-T2, have been used to detect the proteins by immunoblotting and immunofluorescence microscopy, demonstrating their specific synthesis in the testis, late in spermatid differentiation, and their localization in the calyx. The discovery of two novel Arps as major components in a cytoskeletal, nonmotile structure of mammalian spermatozoa suggests that certain members of this family of proteins may serve functions other than nucleation of actin filaments, and possible biological roles of such Arps in spermatozoa are discussed.
顶体是哺乳动物精子头部核周膜的一种大型细胞骨架成分，呈现出显著的种间形态差异，其生化特征是对高离子强度和去污剂具有抗性，且具有特殊的蛋白质组成，包括碱性蛋白钙结合蛋白、环蛋白I和II，以及两种主要的肌动蛋白封端蛋白。在我们从公牛精子制备的顶体制剂中，我们注意到两种主要的酸性成分，经部分氨基酸测序后，已被鉴定为肌动蛋白相关蛋白（Arp）亚家族的新成员。针对相应人类蛋白（称为Arp-T1和Arp-T2）产生的抗体已用于通过免疫印迹和免疫荧光显微镜检测这些蛋白，证明它们在精子细胞分化后期在睾丸中特异性合成，并定位于顶体。在哺乳动物精子的细胞骨架、非运动结构中发现两种新型Arp作为主要成分，这表明该蛋白家族的某些成员可能具有肌动蛋白丝成核以外的功能，并讨论了此类Arp在精子中的可能生物学作用。
