CLONING OF A CDNA FOR LAMINA-ASSOCIATED POLYPEPTIDE-2 (LAP2) AND IDENTIFICATION OF REGIONS THAT SPECIFY TARGETING TO THE NUCLEAR-ENVELOPE
CLONING OF A CDNA FOR LAMINA-ASSOCIATED POLYPEPTIDE-2 (LAP2) AND IDENTIFICATION OF REGIONS THAT SPECIFY TARGETING TO THE NUCLEAR-ENVELOPE
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DOI：
10.1002/j.1460-2075.1995.tb07151.x
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发表时间：
1995-04-18
期刊：
影响因子：
11.4
通讯作者：
GERACE, L
中科院分区：
文献类型：
--
作者：
FURUKAWA, K;PANTE, N;GERACE, L
层相关多肽2(LAP2)是内核膜的一种完整的膜蛋白，它以有丝分裂磷酸化调控的方式与层蛋白B1和染色体直接结合。LAP2的生化和生理特性表明，LAP2在有丝分裂结束时的核膜重组和/或核层和间期染色体与核膜的锚定中发挥重要作用。我们描述了LAP2基因的克隆及其膜的拓扑结构和针对核膜的定位。LAP2的cDNA序列预测了一个由452个氨基酸组成的蛋白质，包含一个大的亲水性结构域，在410-433位残基上有一个可能的跨膜序列，其中有几个潜在的cdc2激酶磷酸化位点。在分离的核膜中对LAP2表位的免疫金定位表明，大的氨基末端亲水结构域(残基1-409)暴露在核质中。通过在培养细胞中表达LAP2的缺失突变体，我们已经在其核质结构域中确定了促进核膜定位的多个区域。这些数据表明，LAP2靶向核膜是通过与核内膜上多个结合位点的协同作用来实现的。
Lamina-associated polypeptide 2 (LAP2) is an integral membrane protein of the inner nuclear membrane, which binds directly to both lamin B1 and chromosomes in a mitotic phosphorylation-regulated manner. The biochemical and physiological properties of LAP2 suggest an important role in nuclear envelope reassembly at the end of mitosis and/or anchoring of the nuclear lamina and interphase chromosomes to the nuclear envelope. We describe the cDNA cloning of LAP2 and characterization of its membrane topology and targeting to the nuclear envelope. The LAP2 cDNA sequence predicts a protein of 452 amino acids, containing a large hydrophilic domain with several potential cdc2 kinase phosphorylation sites and a single putative membrane-spanning sequence at residues 410-433. Immunogold localization of an LAP2 epitope in isolated nuclear envelopes indicates that the large amino-terminal hydrophilic domain (residues 1-409) is exposed to the nucleoplasm. By expressing deletion mutants of LAP2 in cultured cells, we have identified multiple regions in its nucleoplasmic domain that promote localization at the nuclear envelope. These data suggest that targeting of LAP2 to the nuclear envelope is mediated by cooperative interactions with multiple binding sites at the inner nuclear membrane.