15-Deoxyspergualin hinders physical interaction between basic residues of transit peptide in PfENR and Hsp70-1.
The apicoplast of Plasmodium harbors several metabolic pathways. The enzymes required to perform these reactions are all nuclearly encoded and apicoplast targeted (NEAT) proteins. Plasmodium falciparum Enoyl-ACP Reductase (PfENR) is one such NEAT protein. The NEAT proteins have a transit peptide which is required for crossing the membranes of apicoplast. We studied the importance of basic residues like Arginine and Lysine within the transit peptide. Previous studies have suggested that all basic residues are essential for apicoplast trafficking. In this study, we demonstrate that only some of these residues are essential (K44, R48, K51, and R52), whereas others are dispensable (R40, K42, and K49). On mutating these specific residues, PfENR is not imported into the apicoplast and is mislocalized to the cytoplasm. We also demonstrate that these residues are also crucial for interaction with Hsp70-1, implying that interactions of Lysine 44, Arginine 48, Lysine 51, and Arginine 52 of the transit peptide with PfHsp70-1 are required for apicoplast trafficking. 15-Deoxyspergualin, which has earlier been proposed to interact with EEVD motif of PfHsp70-1 hinders the physical interaction between these cationic residues of PfENR and Hsp70-1. Hence, we propose that in the transport competent state of NEAT proteins some specific positively charged amino acids in the transit peptide interact with PfHsp70-1, and this interaction is essential for apicoplast targeting.
Molecular Sciences Laboratory, National Institute of Immunology, New Delhi 110067, India.
Tanushree
T
Banerjee
Rajiv Ranjan
RR
Singh
Sarika
S
Gupta
Avadhesha
A
Surolia
Namita
N
Surolia
D024361:Amino Acids, Basic / Q000378:metabolism; D000962:Antimalarials / Q000494:pharmacology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006146:Guanidines / Q000494:pharmacology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D015388:Organelles / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D021382:Protein Sorting Signals; D021381:Protein Transport; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D024361:Amino Acids, Basic; D000962:Antimalarials; D006146:Guanidines; D018840:HSP70 Heat-Shock Proteins; D020033:Protein Isoforms; D021382:Protein Sorting Signals; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D044925:Oxidoreductases Acting on CH-CH Group Donors; C037258:gusperimus