Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan.
J Struct Biol. 2012 Aug;179(2):138-42. doi: 10.1016/j.jsb.2012.04.010. Epub 2012 Apr 27.
Spastin belongs to the meiotic subfamily, together with Vps4/SKD1, fidgetin and katanin, of AAA (ATPases associated with diverse cellular activities) proteins, and functions in microtubule severing. Interestingly, all members of this subgroup specifically contain an additional α-helix at the very C-terminal end. To understand the function of the C-terminal α-helix, we characterised its deletion mutants of SPAS-1, a Caenorhabditis elegans spastin homologue, in vitro and in vivo. We found that the C-terminal α-helix plays essential roles in ATP binding, ATP hydrolysing and microtubule severing activities. It is likely that the C-terminal α-helix is required for cellular functions of members of meiotic subgroup of AAA proteins, since the C-terminal α-helix of Vps4 is also important for assembly, ATPase activity and in vivo function mediated by ESCRT-III complexes.
Spastin 属于减数分裂亚家族，与 Vps4/SKD1、fidgetin 和 katanin 一起，属于 AAA（与多种细胞活动相关的 ATP 酶）蛋白，并在微管切割中发挥作用。有趣的是，该亚组的所有成员都在非常 C 末端特别含有一个额外的α-螺旋。为了了解 C 末端α-螺旋的功能，我们在体外和体内对 Caenorhabditis elegans spastin 同源物 SPAS-1 的 C 末端α-螺旋缺失突变体进行了表征。我们发现 C 末端α-螺旋在 ATP 结合、ATP 水解和微管切割活性中起着重要作用。很可能 C 末端α-螺旋对于减数分裂亚家族 AAA 蛋白的细胞功能是必需的，因为 Vps4 的 C 末端α-螺旋对于 ESCRT-III 复合物介导的组装、ATP 酶活性和体内功能也很重要。
