Do F-box proteins with a C-terminal domain homologous with the tobacco lectin play a role in protein degradation in plants?
Do F-box proteins with a C-terminal domain homologous with the tobacco lectin play a role in protein degradation in plants?
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DOI：
10.1042/bst0360843
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发表时间：
2008-10-01
影响因子：
3.9
通讯作者：
Van Damme, Els J. M.
中科院分区：
文献类型：
--
作者：
Lannoo, Nausicaa;Peumans, Willy J.;Van Damme, Els J. M.
蛋白质周转是调节许多细胞过程的关键翻译后事件。它使细胞能够通过调整关键蛋白质的水平来快速响应细胞内信号和不断变化的环境条件。主要的蛋白水解途径涉及靶蛋白的泛素化以及随后靶向 26S 蛋白酶体进行降解。许多 F-box 蛋白在此降解途径的底物特异性中发挥着决定性作用。在大多数情况下，目标蛋白的选择性识别依赖于 F-box 蛋白 C 端结构域介导的蛋白间相互作用。在哺乳动物中，具有 C 端 SBD（糖结合域）的 F-box 蛋白的出现已被证实，该蛋白与目标糖蛋白上的高甘露糖 N-聚糖特异性相互作用。这些糖结合 F-box 蛋白的鉴定和表征表明，F-box 蛋白不仅利用蛋白质-蛋白质相互作用，还利用 Ub（泛素）/蛋白酶体途径中的蛋白质-碳水化合物相互作用。最近，在植物中鉴定出了假定的糖结合 F-box 蛋白。拟南芥和水稻的基因组分析揭示了 F-box 蛋白的存在，其 C 端凝集素相关结构域与 Nictaba 同源，Nictaba 是一种来自烟草的茉莉酸诱导型凝集素，已被证明与高甘露糖和复杂 N-聚糖的核心结构相互作用。由于 Nictaba 和哺乳动物 Fbs 蛋白的 SBD 在结构和特异性上高度相似，因此表明具有 Nictaba 结构域的植物 F-box 蛋白在植物细胞核质蛋白降解中具有类似的作用。
Protein turnover is a key post-translational event that regulates numerous cellular processes. it enables cells to respond rapidly to intracellular signals and changing environmental conditions by adjusting the levels of pivotal proteins. A major proteolytic pathway involves the ubiquitination of target proteins and subsequent targeting to the 26S proteasome for degradation. Many F-box proteins play a determining role in the substrate specificity of this degradation pathway. In most cases, selective recognition of the target proteins relies on protein-protein interactions mediated by the C-terminal domain of the F-box proteins. In mammals, the occurrence of F-box proteins with a C-terminal SBD (sugar-binding domain) that specifically interacts with high-mannose N-glycans on target glycoproteins has been documented. The identification and characterization of these sugar-binding F-box proteins demonstrated that F-box proteins do not exclusively use protein-protein interactions but also protein-carbohydrate interactions in the Ub (ubiquitin)/proteasome pathway. Recently, putative sugar-binding F-box proteins have been identified in plants. Genome analyses in Arabidopsis and rice revealed the presence of F-box proteins with a C-terminal lectin-related domain homologous with Nictaba, a jasmonate-inducible lectin from tobacco that was shown to interact with the core structure of high-mannose and complex N-glycans. Owing to the high similarity in structure and specificity between Nictaba and the SBD of the mammalian Fbs proteins, a similar role for the plant F-box proteins with a Nictaba domain in nucleocytoplasmic protein degradation in plant cells is suggested.