CLIPB4 is a central node in the protease network that regulates humoral immunity in Anopheles gambiae mosquitoes.
CLIPB4 is a central node in the protease network that regulates humoral immunity in Anopheles gambiae mosquitoes.
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CLIPB4 是调节冈比亚按蚊体液免疫的蛋白酶网络的中心节点。
DOI：
10.1101/2023.07.07.545904
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Michel,Kristin
中科院分区：
文献类型：
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作者：
Zhang,Xiufeng;Zhang,Shasha;Kuang,Junyao;Sellens,KathleenA;Morejon,Bianca;Saab,SallyA;Li,Miao;Metto,EveC;An,Chunju;Culbertson,ChristopherT;Osta,MikeA;Scoglio,Caterina;Michel,Kristin
昆虫的体液免疫反应在一定程度上受蛋白酶级联反应的调节，蛋白酶级联反应的成分在血淋巴中作为酶原循环。在蚊子中，这些级联由剪切结构域丝氨酸蛋白酶（cSPs）和/或它们的非催化同源物组成，它们形成了一个复杂的网络，其分子组成尚不完全清楚。利用系统生物学方法，基于使用丝氨酸蛋白酶抑制剂（SRPN） 2（蚊子黑化反应的关键负调节因子）在黑化和共免疫沉淀中起作用的基因家族成员的共表达网络，我们确定了来自非洲疟蚊冈比亚按蚊的cSP CLIPB4作为该蛋白酶网络的中心节点。CLIPB4与SRPN2紧密共表达，并在免疫攻击雌蚊的血淋巴中与SRPN2形成蛋白复合物。遗传和生化方法验证了我们的网络分析，并表明CLIPB4是黑色素化和抗菌免疫所必需的，它是一种被SRPN2抑制的酚氧化酶（proPO）激活蛋白酶。此外，我们提供了新的见解，以cSP网络的结构组织在安。gambiae，通过证明CLIPB4能够激活proCLIPB8， proCLIPB8是proppo激活蛋白酶CLIPB9上游的cSP。这些数据提供了第一个证据，证明在蚊子中，csp在免疫蛋白酶网络中提供分支点，并在proPO激活级联中传递正强化。
Insect humoral immune responses are regulated in part by protease cascades, whose components circulate as zymogens in the hemolymph. In mosquitoes, these cascades consist of clip-domain serine proteases (cSPs) and/or their non-catalytic homologs, which form a complex network, whose molecular make-up is not fully understood. Using a systems biology approach, based on a co-expression network of gene family members that function in melanization and co-immunoprecipitation using the serine protease inhibitor (SRPN) 2, a key negative regulator of the melanization response in mosquitoes, we identify the cSP CLIPB4 from the African malaria mosquito Anopheles gambiae as a central node in this protease network. CLIPB4 is tightly co-expressed with SRPN2 and forms protein complexes with SRPN2 in the hemolymph of immune-challenged female mosquitoes. Genetic and biochemical approaches validate our network analysis and show that CLIPB4 is required for melanization and antibacterial immunity, acting as a prophenoloxidase (proPO)-activating protease, which is inhibited by SRPN2. In addition, we provide novel insight into the structural organization of the cSP network in An. gambiae, by demonstrating that CLIPB4 is able to activate proCLIPB8, a cSP upstream of the proPO-activating protease CLIPB9. These data provide the first evidence that, in mosquitoes, cSPs provide branching points in immune protease networks and deliver positive reinforcement in proPO activation cascades.