Harborth J, Osborn M
Max Planck Institute for Biophysical Chemistry, Goettingen, Germany.
Crit Rev Eukaryot Gene Expr. 1999;9(3-4):319-28. doi: 10.1615/critreveukargeneexpr.v9.i3-4.160.
We review the properties of NuMA, concentrating on a possible role for NuMA as a scaffold protein in the interphase nucleus. NuMA is a component of the nuclear matrix in interphase cells and translocates to the spindle poles in mitosis. NuMA has a secondary structure in which a long central rod domain that forms a double-stranded coiled coil is flanked by globular terminal domains. In vitro assembly experiments with bacterially expressed recombinant protein showed that NuMA seems not to form filaments, but instead builds multiarm oligomers by interaction of the C-terminal globular domains. Transient overexpression of NuMA in HeLa cells induced the formation of a three-dimensional lattice with a quasihexagonal organization that fills the nucleus. Use of mutant constructs showed that the lattice spacing depended on the length of the rod domain. Using a 12-arm oligomer as the structural unit, computer modeling can explain the observed nuclear lattices. The flexibility of the NuMA molecule as well as its dynamic capacity to form lattices is a hint that NuMA may play a structural role in the architecture of the normal interphase nucleus.
我们回顾了核有丝分裂器蛋白（NuMA）的特性，重点关注其作为间期细胞核中支架蛋白的可能作用。NuMA是间期细胞中核基质的一个组成部分，在有丝分裂时会转移到纺锤体极。NuMA具有二级结构，其中一个形成双链卷曲螺旋的长中央杆状结构域两侧是球状末端结构域。用细菌表达的重组蛋白进行的体外组装实验表明，NuMA似乎不形成细丝，而是通过C末端球状结构域的相互作用形成多臂寡聚体。在HeLa细胞中瞬时过表达NuMA会诱导形成一种三维晶格，其具有填充细胞核的准六边形组织。使用突变体构建体表明晶格间距取决于杆状结构域的长度。以12臂寡聚体作为结构单元，计算机建模可以解释观察到的核晶格。NuMA分子的灵活性及其形成晶格的动态能力暗示NuMA可能在正常间期细胞核的结构中发挥结构作用。
