Dynamic Palmitoylation of Red Cell Membrane Proteins Governs Susceptibility to Invasion by the Malaria Parasite, Plasmodium falciparum

Abstract

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, Plasmodium falciparum. 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 P. falciparum invasion.

CRISPR/Cas9-engineering of Kell null erythrocytes to unveil host targeted irresistible antimalarial

“…In the current study, we comprehensively investigate the functional significance of the protease activity associated with Kell surface proteases and subsequently identified a highly effective, Kell-specific inhibitory compound. Our previous research demonstrated a substantial reduction in invasion efficiency upon exposure to Kell-specific antibodies 9 , underscoring a potential link between Kell and the invasion process. To comprehensively ascertain Kell's significance in the invasion, we adopted a CRISPR-Cas9-based approach to knockout the kell gene in an immortalized erythroid progenitor cell line, BEL-A 15 .…”

“…In our pursuit of identifying erythrocytic proteases crucial for parasite invasion, we underscored the functional significance of the Kell blood group antigen 9 . Kell belongs to the neprilysin (M13) family of zinc endopeptidases and are the third most potent immunogenic system after ABO and Rh system [10][11][12] .…”

Identification of a De Novo Peptide against Palmitoyl Acyltransferase 6 to Block Survivability and Infectivity of Leishmania donovani

“…Furthermore, we annotated 20 protein sequences having DHHC domains in Ld PATs for the first time, providing insight into their possible functions. Furthermore, we elucidated the significance of global palmitoylation in parasite growth and survival. , …”

“…Furthermore, we elucidated the significance of global palmitoylation in parasite growth and survival. 13,20 In the current investigation, we combined in vitro parasitic based studies, in silico analysis, and biophysical assays to investigate the functional role of novel palmitoyl acyltransferase LdPAT6 in parasitic invasion and discovered a novel inhibitor against LdPAT6 for future chemotherapeutics. Employing a B2H assay approach, we discovered novel peptide inhibitors targeting the DHHC domain of LdPAT6, including a noteworthy 28-amino acid de novo peptide inhibitor denoted PS1 [Figure 2B(ii)].…”

Generation of red blood cells from stem cells: Achievements, opportunities and perspectives for malaria research

“…Site specific requirements of host cell proteins in malaria parasite invasion, development and host remodelling have been widely documented and postulated, with many as yet unidentified contributions undoubtedly still to be uncovered. These range from single nucleotide polymorphisms, sites of glycosylation ( Goerdeler et al., 2021 ) and palmitoylation ( Kumari et al., 2022 ) of receptors to phosphorylation sites within membrane and cytoskeletal adaptor proteins. By enabling their alteration (deletion, disruption or replacement with phospho-modification incompetent residues for example), immortalised erythroid cell lines allow for the role of such sites to be dissected within a true cellular context, providing a powerful tool for new mechanistic insight.…”