Human biliverdin reductase is a leucine zipper-like DNA-binding protein and functions in transcriptional activation of heme oxygenase-1 by oxidative stress
Human biliverdin reductase is a leucine zipper-like DNA-binding protein and functions in transcriptional activation of heme oxygenase-1 by oxidative stress
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DOI：
10.1074/jbc.m108239200
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发表时间：
2002-03-15
影响因子：
4.8
通讯作者：
Maines, MD
中科院分区：
文献类型：
--
作者：
Ahmad, Z;Salim, M;Maines, MD
人胆绿素还原酶（hBVR）是一种丝氨酸/苏氨酸激酶，催化血红素加氧酶（HO）活性产物胆绿素还原为胆红素。胆绿素还原酶（BVR）的结构域具有类似于亮氨酸拉链蛋白的一级结构特征。五个亮氨酸的七肽重复（L-1-L-5）、碱性结构域和保守的丙氨酸表征该结构域。在hBVR中，赖氨酸取代L-3。hBVR的二级结构模型预测了该结构域的α-螺旋-转角-β-折叠。用兔网织红细胞裂解物系统翻译的hBVR在非变性凝胶上显示为单一条带，分子量约为69 kDa。变性凝胶上的蛋白质分离成两种类似于39.9 + 34.6 kDa的抗hBVR免疫反应性蛋白。二聚体形式，但不是纯化的hBVR，结合到一个100聚体的DNA片段，对应于小鼠HO-1（hsp 32）启动子区，包括两个激活蛋白（AP-1）的网站。DNA结合的特异性表现在：（a）hBVR不与具有一个或零个AP-1位点的相同DNA片段结合;（B）具有一个AP-1位点的56-bp随机DNA不与hBVR形成复合物;（c）体外翻译的HO-1不与具有两个AP-1位点的100-mer DNA片段相互作用;（d）Lys（143）、Leu（150）或Leu（157）的突变阻断了类似于69-kDa样品的形成和hBVR DNA复合物的形成;（e）hBVR或hHO-1的纯化制剂不与具有两个AP-1位点的DNA结合。在稳定转染反义hBVR的COS细胞中，HO-1对超氧阴离子（O-2（.））的反应降低了66%，表明AP-1结合的潜在意义。甲萘醌的诱导作用减弱，而血红素的诱导作用不受影响。我们提出BVR在HO-1氧化应激反应所必需的AP-1复合物激活的信号级联中的作用。
Human biliverdin reductase (hBVR) is a serine/threonine kinase that catalyzes reduction of the heme oxygenase (HO) activity product, biliverdin, to bilirubin. A domain of biliverdin reductase (BVR) has primary structural features that resemble leucine zipper proteins. A heptad repeat of five leucines (L-1-L-5), a basic domain, and a conserved alanine characterize the domain. In hBVR, a lysine replaces L-3. The secondary structure model of hBVR predicts an alpha-helix-turn-beta-sheet for this domain. hBVR translated by the rabbit reticulocyte lysate system appears on a nondenaturing gel as a single band with molecular mass of similar to69 kDa. The protein on a denaturing gel separates into two anti-hBVR immunoreactive proteins of similar to39.9 + 34.6 kDa. The dimeric form, but not purified hBVR, binds to a 100-mer DNA fragment corresponding to the mouse HO-1 (hsp32) promoter region encompassing two activator protein (AP-1) sites. The specificity of DNA binding is suggested by the following: (a) hBVR does not bind to the same DNA fragment with one or zero AP-1 sites; (b) a 56-bp random DNA with one AP-1 site does not form a complex with hBVR; (c) in vitro translated HO-1 does not interact with the 100-mer DNA fragment with two AP-1 sites; (d) mutation of Lys(143), Leu(150), or Leu(157) blocks both the formation of the similar to69-kDa specimens and hBVR DNA complex formation; and (e) purified preparations of hBVR or hHO-1 do not bind to DNA with two AP-1 sites. The potential significance of the AP-1 binding is suggested by the finding that the response of HO-1, in COS cells stably transfected with antisense hBVR, with 66% reduced BVR activity, to superoxide anion (O-2(.)) formed by menadione is attenuated, whereas induction by heme is not affected. We propose a role for BVR in the signaling cascade for AP-1 complex activation necessary for HO-1 oxidative stress response.