CX3CL1 binding protein-2 (CBP2) of Plasmodium falciparum binds nucleic acids

Abstract

Several exported Plasmodium falciparum(Pf) proteins contribute to malaria biology through their involvement in cytoadherence, immune evasion and host cell remodelling. Many of these exported proteins and other host molecules are present in iRBC (infected red blood cell) generated extracellular vesicles (EVs), which are responsible for host cell modification and parasite development. CX3CL1 binding proteins (CBPs) present on the surface of iRBC have been reported to contribute to cytoadhesion by binding with the chemokine 'CX3CL1' via their extracellular domains. Here, we have characterized the cytoplasmic domain of CBP2to understand its function in parasite biology using biochemical and biophysical methods.Recombinant cytoplasmic CBP2 (rcCBP2) binds nucleic acids showing interaction with DNA/RNA. rcCBP2 shows dimer formation under non-reducing conditions highlighting the role of disulphide bonds in oligomerization while ATP binding leads to structural changes in the protein. In vitro interaction studies depict its binding with a Maurer's cleft resident protein 'PfSBP1', which is influenced by ATP binding of rcCBP2. Our results suggest CBP2 as a two-

Extracellular vesicles derived from Plasmodium-infected and non-infected red blood cells as targeted drug delivery vehicles

“…The internalization of pRBC-EVs by other pRBCs (Mantel et al, 2013;Regev-Rudzki et al, 2013) and their role in intercellular communication affecting malaria pathogenesis have been described in the literature (Mantel et al, 2013;Regev-Rudzki et al, 2013;Saxena et al, 2019;Sisquella et al, 2017). However, to date, of our knowledge, there is no description of the role of EVs in physiological communication between RBCs.…”

“…These molecular cargos have potential roles in intercellular communication (Regev-Rudzki et al, 2013), modulation of immune response (Saxena et al, 2019;Sisquella et al, 2017), and parasite survival and malaria pathogenesis (Mantel and Marti, 2014;Mantel et al, 2013;Marcilla et al, 2014;Ofir-Birin et al, 2017;Regev-Rudzki et al, 2013). It was also shown that EVs derived from pRBCs can be internalized and transmit genetic material to other pRBCs (Mantel et al, 2013;Regev-Rudzki et al, 2013), monocytes (Sisquella et al, 2017) and endothelial cells (Saxena et al, 2019).…”

Investigating the ATP-binding pocket of CX3CL1-binding protein 2 using in silico approach

“…Both, CBP2 as receptor and ATP as ligand were prepared using CHIMERA in PDBQT format. Based on predictions from ATPint & ATPbind and information based on our report of ATP binding to recombinant cCBP2 [19], a grid box was selected to perform the docking. Others parameters for ligand and receptor were set to default [31].…”

“…It is believed that PfSBP1 resides in Maurer's clefts and works with other proteins like MAHRP1, Pf322, REX1, and REX2 to transport PfEMP1 [18]. The cytoplasmic domain of CBP2 (cCBP2) is also known to directly bind PfSBP1, nucleic acids (DNA/RNA) and ATP [19]. Furthermore, both PfSBP1 and CBP2 have been found to be present in extracellular vesicles (EVs) produced by parasitized RBCs.…”

“…ATP binding of 2TM protein 'CBP2' is suggestive of its role as a purinergic receptor that effects cellular signaling. Binding of cCBP2 with ATP induced structural changes in the protein leading to its oligomerization [19]. ATP binding negatively impacted the interaction between cCBP2 and PfSBP1.…”