Gotzmann J, Foisner R
Institute of Tumor Biology-Cancer Research, University of Vienna, Austria.
Crit Rev Eukaryot Gene Expr. 1999;9(3-4):257-65. doi: 10.1615/critreveukargeneexpr.v9.i3-4.100.
Lamins are the major components of the nuclear lamina, a two-dimensional filamentous network at the periphery of the nucleus in higher eukaryotes, directly underlying the inner nuclear membrane. Several integral proteins of the inner nuclear membrane bind to lamins and may link the nuclear membrane to the core lamina network. The lamins and the lamin-binding proteins lamina-associated polypeptide (LAP)2beta and lamin B receptor (LBR) have been described to bind to DNA or to interact with chromatin via histones, BAF-1, and HP1 chromodomain proteins, respectively, and may provide anchorage sites for chromatin fibers at the nuclear periphery. In addition, lamin A structures on intranuclear filaments, or lamin B in replication foci have been described in the nuclear interior, but their specific roles remain unclear. An isoform of the LAP2 protein family, LAP2alpha, has been found to colocalize with A-type lamins in the nucleoplasm and might be involved in intranuclear structure organization. In the course of cell-cycle-dependent dynamics of the nucleus in higher eukaryotes, lamins as well as lamin-binding proteins seem to possess important functions during various steps of post-mitotic nuclear reassembly, including cross-linking of chromatides, nuclear membrane targeting, nuclear lamina assembly, and the formation of a replication-competent nucleus.
核纤层蛋白是核纤层的主要成分，核纤层是高等真核生物细胞核周边的二维丝状网络，直接位于内核膜下方。内核膜的几种整合蛋白与核纤层蛋白结合，并可能将核膜与核心核纤层网络相连。核纤层蛋白以及与核纤层蛋白结合的蛋白——核纤层相关多肽（LAP）2β和核纤层蛋白B受体（LBR），分别被描述为可与DNA结合或通过组蛋白、BAF-1和HP1染色质结构域蛋白与染色质相互作用，并且可能为核周边的染色质纤维提供锚定位点。此外，在核内部已描述了核内细丝上的核纤层蛋白A结构或复制灶中的核纤层蛋白B，但其具体作用仍不清楚。已发现LAP2蛋白家族的一种异构体LAP2α与A型核纤层蛋白在核质中共定位，可能参与核内结构组织。在高等真核生物细胞核依赖细胞周期的动态变化过程中，核纤层蛋白以及与核纤层蛋白结合的蛋白在有丝分裂后核重新组装的各个步骤中似乎都具有重要功能，包括染色单体交联、核膜靶向、核纤层组装以及形成具有复制能力的细胞核。
