The geminivirus nuclear shuttle protein is a virulence factor that suppresses transmembrane receptor kinase activity
The geminivirus nuclear shuttle protein is a virulence factor that suppresses transmembrane receptor kinase activity
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DOI：
10.1101/gad.1245904
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发表时间：
2004-10-15
影响因子：
10.5
通讯作者：
Chory, J
中科院分区：
文献类型：
--
作者：
Fontes, EPB;Santos, AA;Chory, J
尽管在植物中存在大量的富含亮氨酸重复序列（LRR）的受体样激酶（RLK）及其在信号事件中的概念相关性，但功能信息仅限于。一些家庭成员。在这里，我们描述了新的LRR-RLK家族成员作为双生病毒核穿梭蛋白（NSP）的毒力靶点的特征。NSP通过包含激酶活性位点和A环的80个氨基酸区域与三种LRR-RLK（NIK 1、NIK 2和NIK 3）特异性相互作用。我们证明，这些NSP相互作用激酶（NIKs）是膜定位的蛋白质与信号受体的生化特性。它们表现为经历自磷酸化的真实激酶蛋白，也可以磷酸化外源底物。自磷酸化通过分子间事件发生，寡聚化先于激酶的活化。NSP与NIK的结合在体外抑制其激酶活性，表明NIK参与抗病毒防御反应。为了支持这一点，感染性测定显示感染率与NIK 1和NIK 3功能丧失之间呈正相关。我们的数据与NSP作为毒力因子抑制NIK介导的抗病毒反应的模型一致。
Despite the large number of leucine-rich-repeat (LRR) receptor-like-kinases (RLKs) in plants and their conceptual relevance in signaling events, functional information is restricted to. a few family members. Here we describe the characterization of new LRR-RLK family members as virulence targets of the geminivirus nuclear shuttle protein (NSP). NSP interacts specifically with three LRR-RLKs, NIK1, NIK2, and NIK3, through an 80-amino acid region that encompasses the kinase active site and A-loop. We demonstrate that these NSP-interacting kinases (NIKs) are membrane-localized proteins with biochemical properties of signaling receptors. They behave as authentic kinase proteins that undergo autophosphorylation and can also phosphorylate exogenous substrates. Autophosphorylation occurs via an intermolecular event and oligomerization precedes the activation of the kinase. Binding of NSP to NIK inhibits its kinase activity in vitro, suggesting that NIK is involved in antiviral defense response. In support of this, infectivity assays showed a positive correlation between infection rate and loss of NIK1 and NIK3 function. Our data are consistent with a model in which NSP acts as a virulence factor to suppress NIK-mediated antiviral responses.