BACKGROUND Nicotinamide adenine dinucleotide (NAD) plays a central role in energy
metabolism and integrates cellular metabolism with signalling and gene
expression. NAD biosynthesis depends on the enzyme nicotinamide/nicotinate
mononucleotide adenylyltransferase (NMNAT; EC: 2.7.7.1/18), in which
converge the de novo and salvage pathways.OBJECTIVE The purpose of this study was to analyse the protein-protein interactions
(PPI) of NMNAT of Leishmania braziliensis (LbNMNAT) in
promastigotes.METHODS Transgenic lines of L. braziliensis
promastigotes were established by transfection with the
pSP72αneoαLbNMNAT-GFP vector. Soluble protein extracts were prepared,
co-immunoprecipitation assays were performed, and the co-immunoprecipitates
were analysed by mass spectrometry. Furthermore, bioinformatics tools such
as network analysis were applied to generate a PPI network.FINDINGS Proteins involved in protein folding, redox homeostasis, and translation
were found to interact with the LbNMNAT protein. The PPI network indicated
enzymes of the nicotinate and nicotinamide metabolic routes, as well as
RNA-binding proteins, the latter being the point of convergence between our
experimental and computational results.MAIN CONCLUSION We constructed a model of PPI of LbNMNAT and showed its association with
proteins involved in various functions such as protein folding, redox
homeostasis, translation, and NAD synthesis.