Substrate specificity of Pasteurella multocida toxin for α subunits of heterotrimeric G proteins
Substrate specificity of Pasteurella multocida toxin for α subunits of heterotrimeric G proteins
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DOI：
10.1096/fj.12-213900
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发表时间：
2013-02-01
期刊：
影响因子：
4.8
通讯作者：
Aktories, Klaus
中科院分区：
文献类型：
--
作者：
Orth, Joachim H. C.;Fester, Ines;Aktories, Klaus
多杀性巴氏杆菌是许多动物流行病和人畜共患疾病的病原体。其与动物萎缩性鼻炎和咬伤皮肤坏死相关的主要毒力因子是多杀性巴氏杆菌毒素（PMT）。 PMT 刺激异源三聚体 G 蛋白下游的信号转导途径，导致有丝分裂、细胞凋亡阻断或成骨细胞分化抑制等效应。在 G α(i2) 的基础上，证明该毒素使 G α(i2) 亚基的必需谷氨酰胺残基脱酰胺，导致 G 蛋白的组成型激活。在这里，我们通过质谱分析和利用单克隆抗体研究了 PMT 对其 G 蛋白靶标的特异性，该单克隆抗体特异性识别 PMT 脱酰胺基的 G 蛋白。研究表明，异源三聚体 G 蛋白的 4 个家族（小鼠或人类来源的 G α(q/11)、G α(i1,2,3) 和 G α(12/13)）中的 3 个可通过 PMT 脱酰胺，但不能通过催化失活毒素突变体脱酰胺。利用G蛋白片段和响应性或无响应性G蛋白的嵌合体，研究了区分异源三聚体G蛋白的结构基础。我们的结果在分子水平上阐明了 PMT 的底物特异性，并为底物歧视的根本结构原因提供了证据。-Orth, J. H. C., Fester, I., Siegert, P., Weise, M., Lanner, U., Kamitani, S., Tachibana, T, Wilson, B. A., Schlosser, A., Horiguchi, Y., Aktories, K. 巴斯德氏菌的底物特异性针对异三聚体 G 蛋白的 α 亚基的多杀性毒素。 FASEB J. 27, 832-842 (2013)。 www.fasebj.org
Pasteurella multocida is the causative agent of a number of epizootic and zoonotic diseases. Its major virulence factor associated with atrophic rhinitis in animals and dermonecrosis in bite wounds is P. multocida toxin (PMT). PMT stimulates signal transduction pathways downstream of heterotrimeric G proteins, leading to effects such as mitogenicity, blockade of apoptosis, or inhibition of osteoblast differentiation. On the basis of G alpha(i2), it was demonstrated that the toxin deamidates an essential glutamine residue of the G alpha(i2) subunit, leading to constitutive activation of the G protein. Here, we studied the specificity of PMT for its G-protein targets by mass spectrometric analyses and by utilizing a monoclonal antibody, which recognizes specifically G proteins deamidated by PMT. The studies revealed deamidation of 3 of 4 families of heterotrimeric G proteins (G alpha(q/11), G alpha(i1,2,3), and G alpha(12/13) of mouse or human origin) by PMT but not by a catalytic inactive toxin mutant. With the use of G-protein fragments and chimeras of responsive or unresponsive G proteins, the structural basis for the discrimination of heterotrimeric G proteins was studied. Our results elucidate substrate specificity of PMT on the molecular level and provide evidence for the underlying structural reasons of substrate discrimination.-Orth, J. H. C., Fester, I., Siegert, P., Weise, M., Lanner, U., Kamitani, S., Tachibana, T, Wilson, B. A., Schlosser, A., Horiguchi, Y., Aktories, K. Substrate specificity of Pasteurella multocida toxin for alpha subunits of heterotrimeric G proteins. FASEB J. 27, 832-842 (2013). www.fasebj.org