Colocalization, Physical, and Functional Interaction between Werner and Bloom Syndrome Proteins*
Colocalization, Physical, and Functional Interaction between Werner and Bloom Syndrome Proteins*
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DOI：
10.1074/jbc.m200914200
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发表时间：
2002-06
期刊：
影响因子：
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通讯作者：
C. von Kobbe;P. Karmakar;Lale Dawut;P. Opresko;Xianmin Zeng;R. Brosh;I. Hickson;V. Bohr
中科院分区：
文献类型：
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作者：
C. von Kobbe;P. Karmakar;Lale Dawut;P. Opresko;Xianmin Zeng;R. Brosh;I. Hickson;V. Bohr
RecQ解旋酶家族由一组保守的蛋白质组成，与DNA代谢的几个方面有关。其中三名家庭成员患有遗传性疾病，特征是生长异常、过早衰老和易患恶性肿瘤。这些包括Werner和Bloom综合征中有缺陷的WRN和BLM基因产物，这些疾病具有许多表型和细胞特征，包括自发的基因组不稳定。在这里，我们报告了BLM和WRN之间的物理和功能相互作用。这些蛋白是从核基质溶解部分中免疫共沉淀出来的，纯化的重组蛋白被证明是直接相互作用的。此外，在三个人类细胞系中，BLM和WRN共定位于核焦点。确定了WRN与BLM相互作用的两个区域，其中一个定位于WRN的核酸外切酶结构域。在功能上，BLM抑制WRN的核酸外切酶活性。这是第一次展示了RecQ解旋酶之间的物理和功能相互作用。我们对RecQ家族成员相互作用的观察为这些蛋白的丢失导致的复杂表型表现提供了新的见解。
The RecQ helicase family comprises a conserved group of proteins implicated in several aspects of DNA metabolism. Three of the family members are defective in heritable diseases characterized by abnormal growth, premature aging, and predisposition to malignancies. These include the WRN and BLMgene products that are defective in Werner and Bloom syndromes, disorders which share many phenotypic and cellular characteristics including spontaneous genomic instability. Here, we report a physical and functional interaction between BLM and WRN. These proteins were coimmunoprecipitated from a nuclear matrix-solubilized fraction, and the purified recombinant proteins were shown to interact directly. Moreover, BLM and WRN colocalized to nuclear foci in three human cell lines. Two regions of WRN that mediate interaction with BLM were identified, and one of these was localized to the exonuclease domain of WRN. Functionally, BLM inhibited the exonuclease activity of WRN. This is the first demonstration of a physical and functional interaction between RecQ helicases. Our observation that RecQ family members interact provides new insights into the complex phenotypic manifestations resulting from the loss of these proteins.