Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.
Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
Elife. 2024 Nov 8;13:RP99000. doi: 10.7554/eLife.99000.
The parasitic nematode secretes the HpARI family, which bind to IL-33, either suppressing (HpARI1 and HpARI2) or enhancing (HpARI3) responses to the cytokine. We previously showed that HpARI2 also bound to DNA via its first complement control protein (CCP1) domain. Here, we find that HpARI1 can also bind DNA, while HpARI3 cannot. Through the production of HpARI2/HpARI3 CCP1 domain-swapped chimeras, DNA-binding ability can be transferred, and correlates with in vivo half-life of administered proteins. We found that HpARI1 and HpARI2 (but not HpARI3) also binds to the extracellular matrix component heparan sulphate (HS), and structural modelling showed a basic charged patch in the CCP1 domain of HpARI1 and HpARI2 (but not HpARI3) which could facilitate these interactions. Finally, a mutant of HpARI2 was produced which lacked DNA and HS binding, and was also shown to have a short half-life in vivo. Therefore, we propose that during infection the suppressive HpARI1 and HpARI2 proteins have long-lasting effects at the site of deposition due to DNA and/or extracellular matrix interactions, while HpARI3 has a shorter half-life due to a lack of these interactions.
寄生线虫分泌 HpARI 家族，该家族与 IL-33 结合，抑制（HpARI1 和 HpARI2）或增强（HpARI3）对细胞因子的反应。我们之前表明，HpARI2 还通过其第一个补体控制蛋白 (CCP1) 结构域与 DNA 结合。在这里，我们发现 HpARI1 也可以与 DNA 结合，而 HpARI3 则不能。通过产生 HpARI2/HpARI3 CCP1 结构域交换嵌合体，可以转移 DNA 结合能力，并与给药蛋白的体内半衰期相关。我们发现 HpARI1 和 HpARI2（但不是 HpARI3）也与细胞外基质成分硫酸乙酰肝素 (HS) 结合，结构建模显示 HpARI1 和 HpARI2（但不是 HpARI3）的 CCP1 结构域中存在一个带正电荷的基本斑块，这可能促进了这些相互作用。最后，产生了一种缺乏 DNA 和 HS 结合的 HpARI2 突变体，并且在体内也显示出较短的半衰期。因此，我们提出在感染过程中，由于 DNA 和/或细胞外基质相互作用，抑制性的 HpARI1 和 HpARI2 蛋白在沉积部位具有持久的作用，而 HpARI3 由于缺乏这些相互作用而具有较短的半衰期。
