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

The gene encoding dihydrofolate reductase-thymidylate synthase of the human malaria parasite, Plasmodium vivax, was isolated by polymerase chain reaction from genomic DNA and cloned. The sequences of the dihydrofolate reductase domain of 30 clinical isolates originating from various geographic areas were compared. Interstrain analysis revealed several genotypic variations, including short tandem repeat arrays which produced length polymorphism between different parasite isolates and point mutations in the putative dihydrofolate reductase active site cavity corresponding to those associated with pyrimethamine resistance in P. falciparum and rodent malaria parasites. Amino acid substitutions Ser-->Asn-117 and Ser-->Arg-58 were associated with decreased level of in vitro pyrimethamine sensitivity. These findings suggest that the P. vivax dihydrofolate reductase domain is characterized by polymorphism that has not been observed in P. falciparum and may explain the resistance of some P. vivax isolates to pyrimethamine. Nucleotide sequence data reported in this paper are available in the EMBL, GenBank and DDJB databases under the accession numbers X98123 (isolate ARI/Pakistan), AJ003050 (isolate CNC/Thailand), AJ003051 (isolate COU/unknown geographic origin), AJ003052 (isolate DUF/French Guiana), AJ003053 (isolate GRO/Madagascar), AJ003054 (isolate HRT/Comoros Islands), AJ003071 (isolate LFT/Cambodia), AJ003072 (isolate LGF/'India), AJ003073 (isolate MAN/Comoros Islands), AJ003074 (isolate MAT/Surinam), AJ003075 (isolate PHI/Djibouti), AJ003076 (isolate PIT/Madagascar), AJ003077 (isolate YTZ/Indonesia), AJ222630 (isolate Burma-1), AJ222631 (isolate Burma-151), AJ222632 (isolate Burma-5), AJ222633 (isolate Burma-6), AJ222634 (isolate Burma-98).
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PMID:Sequence variations in the Plasmodium vivax dihydrofolate reductase-thymidylate synthase gene and their relationship with pyrimethamine resistance. 965 31

gp78 is a ubiquitin ligase that plays a vital role in endoplasmic reticulum (ER)-associated degradation (ERAD). Here we report that autocrine motility factor (AMF), also known as phosphoglucose isomerase (PGI), is a novel substrate of gp78. We show that polyubiquitylation of AMF requires cooperative interaction between gp78 and the ubiquitin ligase TRIM25 (tripartite motif-containing protein 25). While TRIM25 mediates the initial round of ubiquitylation, gp78 catalyzes polyubiquitylation of AMF. The E4-like activity of gp78 was illustrated by an in vitro polyubiquitylation assay using Ub-DHFR as a model substrate. We further demonstrate that TRIM25 ubiquitylates gp78 and that overexpression of TRIM25 accelerates the degradation of gp78. Our data suggest that TRIM25 not only cooperates with gp78 in polyubiquitylation of AMF but also gauges the steady-state level of gp78. This study uncovers a previously unknown functional link between gp78 and TRIM25 and provides mechanistic insight into gp78-mediated protein ubiquitylation.
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PMID:Polyubiquitylation of AMF requires cooperation between the gp78 and TRIM25 ubiquitin ligases. 2481 Aug 56