Plasmodium serine hydroxymethyltransferase: indispensability and display of distinct localization

Malar J. 2012 Nov 22;11:387. doi: 10.1186/1475-2875-11-387.


Background: Serine hydroxymethyltransferase (SHMT), a pyridoxal phosphate-dependent enzyme, plays a vital role in the de novo pyrimidine biosynthesis pathway in malaria parasites. Two genes have been identified in Plasmodium spp. encoding a cytosolic SHMT (cSHMT) and putative mitochondria SHMT (mSHMT), but their roles have not been fully investigated.

Methods: The presence of Plasmodium SHMT isoforms in the intra-erythrocytic stage was assessed based on their gene expression using reverse transcription PCR (RT-PCR). Localization studies of Plasmodium SHMT isoforms were performed by transfection of fluorescent-tagged gene constructs into P. falciparum and expressions of fluorescent fusion proteins in parasites were observed using a laser scanning confocal microscope. Genetic targeting through homologous recombination was used to study the essentiality of SHMT in Plasmodium spp.

Results: Semi-quantitative RT-PCR revealed the expression of these two genes throughout intra-erythrocytic development. Localization studies using P. falciparum expressing fluorescent-tagged SHMT showed that PfcSHMT-red fluorescent fusion protein (PfcSHMT-DsRed) is localized in the cytoplasm, while PfmSHMT-green fluorescent fusion protein (PfmSHMT-GFP) co-localized with Mitotracker™-labelled mitochondria as predicted. The essentiality of plasmodial cSHMT was inferred from transfection experiments where recovery of viable knock-out parasites was not achieved, unless complemented with a functional equivalent copy of shmt.

Conclusions: Distinct compartment localizations of PfSHMT were observed between cytoplasmic and mitochondrial isoforms, and evidence was provided for the indispensable role of plasmodial cSHMT indicating it as a valid target for development of novel anti-malarials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytoplasm / chemistry
  • Cytoplasm / enzymology
  • Gene Expression Profiling
  • Gene Knockout Techniques
  • Gene Targeting
  • Genes, Essential
  • Glycine Hydroxymethyltransferase / biosynthesis*
  • Glycine Hydroxymethyltransferase / genetics*
  • Isoenzymes / biosynthesis
  • Isoenzymes / genetics
  • Microscopy, Confocal
  • Mitochondria / chemistry
  • Mitochondria / enzymology
  • Plasmodium falciparum / chemistry
  • Plasmodium falciparum / enzymology*
  • Plasmodium falciparum / genetics
  • Plasmodium falciparum / physiology
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Staining and Labeling


  • Isoenzymes
  • Recombinant Fusion Proteins
  • Glycine Hydroxymethyltransferase