Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.1.3 (dihydrofolate reductase)
 5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We modified an existing selection for protein-protein interactions based on the fragment complementation of the enzyme DHFR. Using shotgun alanine scanning in conjunction with this selection, we analyzed the interaction of the nuclear receptor PPARgamma with two peptides derived from nuclear receptor coactivators SRC1 and TRAP220. A large binding epitope stretching between and including the charge clamp residues K301 and E471 of PPARgamma was identified as necessary for PPARgamma-coactivator interaction. To decouple protein stability from the propensity to form a receptor-coactivator interface, libraries of PPARgamma variants generated by shotgun scanning were further processed using a high-throughput screen measuring their in vivo stabilities. Our findings demonstrate that many of the residues that make up the binding epitope of PPARgamma are also crucial for the stability of the PPARgamma.
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PMID:Binding and stability determinants of the PPARgamma nuclear receptor-coactivator interface as revealed by shotgun alanine scanning and in vivo selection. 1692 49

Acquired resistance to therapeutic agents is a major clinical concern in the prevention/treatment of malaria. The parasite has developed resistance to specific drugs through two mechanisms: mutations in target proteins such as dihydrofolate reductase and the bc1 complex for antifolates and nathoquinones, respectively, and alterations in predicted parasite transporter molecules such as P-glycoprotein homologue 1 (Pgh1) and Plasmodium falciparum CRT (PfCRT). Alterations in the expression of Pgh1 have been associated with modified susceptibility to a range of unrelated drugs. The molecular mechanism(s) that is responsible for this phenotype is unknown. We have shown previously (A. M. Ndifor, R. E. Howells, P. G. Bray, J. L. Ngu, and S. A. Ward, Antimicrob. Agents Chemother. 37:1318-1323, 2003) that the anticonvulsant phenobarbitone (PB) can induce reduced susceptibility to chloroquine (CQ) in P. falciparum, and in the current study, we provide the first evidence for a molecular mechanism underlying this phenomenon. We demonstrate that pretreatment with PB can elicit decreased susceptibility to CQ in both CQ-resistant and CQ-sensitive parasite lines and that this is associated with the increased expression of the drug transporter Pgh1 but not PfCRT. Furthermore, we have investigated the proximal promoter regions from both pfmdr1 and pfcrt and identified a number of putative binding sites for nuclear receptors with sequence similarities to regions known to be activated by PB in mammals. Whole-genome analysis has revealed a putative nuclear receptor gene, providing the first evidence that nuclear receptor-mediated responses to drug exposure may be a mechanism of gene regulation in P. falciparum.
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PMID:Drug-regulated expression of Plasmodium falciparum P-glycoprotein homologue 1: a putative role for nuclear receptors. 1819 56