title: Functional complementation of yeast ribosomal P0 protein with Plasmodium falciparum P0.
abstract: A complex of three phosphoproteins (P0, P1 and P2) constitutes the stalk region at the GTPase center of the eukaryotic large ribosomal subunit, amongst which the protein P0 plays the most crucial role. Earlier studies have shown the functional complementation of the conditional P0-null mutant of Saccharomyces cerevisiae (W303dGP0) with orthologous P0 genes from fungal and mammalian organisms, but not the protozoan parasite Leishmania infantum. In this paper we show that the PfP0 gene from the protozoan malaria parasite Plasmodium falciparum can functionally complement the conditional P0-null W303dGP0 mutant of S. cerevisiae. Unlike the above orthologous genes, PfP0 gene could also rescue the D67dGP0 strain, which in addition to being a conditional null for ScP0 gene, is a null-mutant for both ScP1alpha and beta genes. However, under stress conditions such as high temperature, salt and osmolarity, PfP0 gene could not rescue D67dGP0 strain. Ribosomes purified from W303dGP0 carrying PfP0 gene did not contain ScP1 protein, indicating a lack of binding of ScP1 to PfP0 protein. Yeast 2-hybrid analysis further confirmed the lack of binding of ScP1 to PfP0 protein. The polymerizing activities of ribosomes with ScP0 or PfP0 protein, in the absence of ScP1 protein, were found to be about 40-45% that of ribosomes with all the yeast P-proteins. In its sensitivity to the inhibitor sordarin, PfP0 was similar to the P0 protein from the fungus Aspergillus fumigatus. These results indicate a closer functional relationship of P. falciparum P0 gene to fungal P0 genes.
authors.affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
authors.forename: K
authors.initials: K
authors.lastname: Aruna
authors.forename: Tirtha
authors.initials: T
authors.lastname: Chakraborty
authors.forename: Pavitra N
authors.initials: PN
authors.lastname: Rao
authors.forename: Cruz
authors.initials: C
authors.lastname: Santos
authors.forename: Juan P G
authors.initials: JP
authors.lastname: Ballesta
authors.forename: Shobhona
authors.initials: S
authors.lastname: Sharma
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D001232:Aspergillus fumigatus / Q000235:genetics / Q000378:metabolism; D005816:Genetic Complementation Test / Q000379:methods; D006358:Hot Temperature; D007192:Indenes; D018314:Leishmania infantum / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics* / Q000378:metabolism; D009994:Osmolar Concentration; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D010963:Plasmodium falciparum / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D000935:Antifungal Agents; D007192:Indenes; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011500:Protein Synthesis Inhibitors; D015800:Protozoan Proteins; D012269:Ribosomal Proteins; C483531:SCP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C054675:ribosomal protein P0; C003329:sordarin