Dephosphorylation of T517 on Hemocyanin Is Required for Antibacterial Activity in Penaeus vannamei 
Qian Feng; Jude Juventus Aweya; Yue-Qian Huang; Pei Zhang; Fan Wang 
J Immunol (2023) 210 (9): 1396–1407.
https://doi.org/10.4049/jimmunol.2200598


Abstract
Posttranslational modifications expand the functions of immune-related proteins, especially during infections. The respiratory glycoprotein, hemocyanin, has been implicated in many other functions, but the role of phosphorylation modification in its functional diversity is not fully understood. In this study, we show that Penaeus vannamei hemocyanin (PvHMC) undergoes phosphorylation modification during bacterial infection. Dephosphorylation of PvHMC mediated by P. vannamei protein phosphatase 2A catalytic increases its in vitro antibacterial activity, whereas phosphorylation by P. vannamei casein kinase 2 catalytic subunit α decreases its oxygen-carrying capacity and attenuates its in vitro antibacterial activity. Mechanistically, we show that Thr517 is a critical phosphorylation modification site on PvHMC to modulate its functions, which when mutated attenuates the action of P. vannamei casein kinase 2 catalytic subunit α and P. vannamei protein phosphatase 2A catalytic, and hence abolishes the antibacterial activity of PvHMC. Our results reveal that phosphorylation of PvHMC modulates its antimicrobial functions in penaeid shrimp.


翻译后修饰扩大了免疫相关蛋白的功能，尤其是在感染期间。呼吸糖蛋白血蓝蛋白与许多其他功能有关，但磷酸化修饰在其功能多样性中的作用尚不完全清楚。在本研究中，我们发现南美白对虾血蓝蛋白（PvHMC）在细菌感染过程中发生磷酸化修饰。凡纳滨对虾蛋白磷酸酶2A催化介导的PvHMC的去磷酸化增加了其体外抗菌活性，而凡纳滨滨对虾酪蛋白激酶2催化亚基α的磷酸化降低了其载氧能力并减弱了其体外抑菌活性。从机制上讲，我们发现Thr517是PvHMC上调节其功能的关键磷酸化修饰位点，当突变时，它减弱了凡纳滨对虾酪蛋白激酶2催化亚基α和凡纳滨滨对虾蛋白磷酸酶2A催化的作用，从而消除了PvHMC的抗菌活性。我们的研究结果表明，PvHMC的磷酸化调节其在对虾中的抗菌功能。