Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India.
Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Mangalore 575018, India.
ACS Infect Dis. 2022 Oct 14;8(10):2106-2118. doi: 10.1021/acsinfecdis.2c00199. Epub 2022 Aug 31.
Phosphorylation and other post-translational modifications of red blood cell (RBC) proteins govern membrane function and have a role in the invasion of RBCs by the malaria parasite, . Furthermore, a percentage of RBC proteins are palmitoylated, although the functional consequences are unknown. We establish dynamic palmitoylation of 118 RBC membrane proteins using click chemistry and acyl biotin exchange (ABE)-coupled LC-MS/MS and characterize their involvement in controlling membrane organization and parasite invasion. RBCs were treated with a generic palmitoylation inhibitor, 2-bromopalmitate (2-BMP), and then analyzed using ABE-coupled LC-MS/MS. Only 42 of the 118 palmitoylated proteins detected were palmitoylated in the 2-BMP-treated sample, indicating that palmitoylation is dynamically regulated. Interestingly, membrane receptors such as semaphorin 7A, CR1, and ABCB6, which are known to be involved in merozoite interaction with RBCs and parasite invasion, were found to be dynamically palmitoylated, including the blood group antigen, Kell, whose antigenic abundance was significantly reduced following 2-BMP treatment. To investigate the involvement of Kell in merozoite invasion of RBCs, a specific antibody to its extracellular domain was used. The antibody targeting Kell inhibited merozoite invasion of RBCs by 50%, implying a role of Kell, a dynamically palmitoylated potent host-derived receptor, in parasite invasion. Furthermore, a significant reduction in merozoite contact with the RBC membrane and a consequent decrease in parasite invasion following 2-BMP treatment demonstrated that palmitoylation does indeed regulate RBC susceptibility to parasite invasion. Taken together, our findings revealed the dynamic palmitoylome of RBC membrane proteins and its role in invasion.
红细胞（RBC）蛋白的磷酸化和其他翻译后修饰控制着膜功能，并在疟原虫入侵 RBC 中起作用。此外，一部分 RBC 蛋白被棕榈酰化，尽管其功能后果尚不清楚。我们使用点击化学和酰基辅酶 A 生物素交换（ABE）偶联 LC-MS/MS 方法确定了 118 种 RBC 膜蛋白的动态棕榈酰化，并研究了它们在控制膜组织和寄生虫入侵中的作用。用通用的棕榈酰化抑制剂 2-溴棕榈酸（2-BMP）处理 RBC，然后用 ABE 偶联 LC-MS/MS 进行分析。在 2-BMP 处理的样品中，只有 118 个检测到的棕榈酰化蛋白中的 42 个被棕榈酰化，这表明棕榈酰化是动态调节的。有趣的是，膜受体，如 semaphorin 7A、CR1 和 ABCB6，已知它们参与裂殖子与 RBC 的相互作用和寄生虫入侵，被发现是动态棕榈酰化的，包括血型抗原 Kell，其抗原丰度在 2-BMP 处理后显著降低。为了研究 Kell 在裂殖子入侵 RBC 中的作用，我们使用了针对其细胞外结构域的特异性抗体。针对 Kell 的抗体抑制了 50%的裂殖子入侵 RBC，这表明 Kell 是一个动态棕榈酰化的潜在宿主来源的受体，在寄生虫入侵中起作用。此外，2-BMP 处理后裂殖子与 RBC 膜的接触显著减少，寄生虫入侵相应减少，这表明棕榈酰化确实调节 RBC 对寄生虫入侵的敏感性。总之，我们的研究结果揭示了 RBC 膜蛋白的动态棕榈酰化组及其在寄生虫入侵中的作用。
