LmaPA2G4,a Homolog of Human Ebp1,Is an Essential Gene and Inhibits Cell Proliferation in L. major

We have identified lmapa2g4,a homolog of the human proliferation-associated 2g4 protein (also termed ebp1),in a phosphoproteomic screening. multiple sequence alignment and cluster analysis revealed that lmapa2g4 is a non-peptidase member of the m24 family of metallopeptidases. this pseudoenzyme is structurally related to methionine aminopeptidases. a null mutant system based on negative selection allowed us to demonstrate that lmapa2g4 is an essential gene in leishmania major. over-expression of lmapa2g4 did not alter cell morphology or the ability to differentiate into metacyclic and amastigote stages. interestingly,the over-expression affected cell proliferation and virulence in mouse footpad analysis. lmapa2g4 binds a synthetic double-stranded rna polyriboinosinic polyribocytidylic acid [poly(i:c)] as shown in an electrophoretic mobility shift assay (emsa). quantitative proteomics revealed that the over-expression of lmapa2g4 led to accumulation of factors involved in translation initiation and elongation. significantly,we found a strong reduction of de novo protein biosynthesis in transgenic parasites using a non-radioactive metabolic labeling assay. in conclusion,lmapa2g4 is an essential gene and is potentially implicated in fundamental biological mechanisms,such as translation,making it an attractive target for therapeutic intervention. © 2014 norris-mullins et al.