Identification of host tRNAs preferentially recognized by the Plasmodium surface protein tRip

Abstract

Malaria is a life-threatening and devastating parasitic disease. Our previous work showed that parasite development requires the import of exogenous transfer RNAs (tRNAs), which represents a novel and unique form of host–pathogen interaction, as well as a potentially druggable target. This import is mediated by tRip (tRNA import protein), a membrane protein located on the parasite surface. tRip displays an extracellular domain homologous to the well-characterized OB-fold tRNA-binding domain, a structural motif known to indiscriminately interact with tRNAs. We used MIST (Microarray Identification of Shifted tRNAs), a previously established in vitro approach, to systematically assess the specificity of complexes between native Homo sapiens tRNAs and recombinant Plasmodium falciparum tRip. We demonstrate that tRip unexpectedly binds to host tRNAs with a wide range of affinities, suggesting that only a small subset of human tRNAs is preferentially imported into the parasite. In particular, we show with in vitro transcribed constructs that tRip does not bind specific tRNAs solely based on their primary sequence, hinting that post-transcriptional modifications modulate the formation of our host/parasite molecular complex. Finally, we discuss the potential utilization of the most efficient tRip ligands for the translation of the parasite's genetic information.

Solution X‐ray scattering highlights discrepancies in Plasmodiummulti‐aminoacyl‐tRNA synthetase complexes

“…Indeed, the EMAPII domain of Arc1p (monomeric homolog of tRip) has a preference for yeast tRNA Met and tRNA Glu (Deinert et al, 2001 ) and participates in efficient glutamylation and methionylation in the cell. (Galani et al, 2001 ) On the contrary, the tRNA specificity of the tRip EMAPII ( H. sapiens tRNA Leu , Ser , Asn , Ala ) (Cela et al, 2021 ) does not correlate with the aaRSs found in the Q‐ and M‐ MSCs, suggesting that imported tRNAs play a role beyond their aminoacylation by ERS, MRS and QRS in Plasmodium homeostasis.…”

Comparative proteomics uncovers low asparagine insertion inPlasmodiumtRip-KO proteins

“…We have discovered the only example to date of an exogenous tRNA import pathway, summarized in Fig. 1 [1][2][3][4] . In Plasmodium, the malaria parasite, P. berghei sporozoites (the extracellular infective form of the parasite, Supplementary Fig.…”

“…1) and potentially best imported into the parasite. Interestingly, tRip does not bind to tRNAs in a sequence-dependent manner, but would rather recognize post-transcriptional modifications that modulate this interaction 2 .…”

“…In contrast to what has been shown for its cytosolic homologue Arc1p in Saccharomyces cerevisiae 6 , the tRNAs that best bind tRip do not match the aaRSs that compose MSCs. It suggests that, although tRip is an AIMP, it is not dedicated to the aminoacylation of specific tRNAs (2), thereby leading us to search for a novel function for this unique membrane protein and the tRNA import with which it is associated.…”

“…1) and potentially best imported into the parasite. Interestingly, tRip does not bind to tRNAs in a sequence-dependent manner, but would rather recognize post-transcriptional modifications that modulate this interaction 2 . In contrast to what has been shown for its cytosolic homologue Arc1p in Saccharomyces cerevisiae 6 , the tRNAs that best bind tRip do not match the aaRSs that compose MSCs.…”