Disease relevance of DCP1

• To determine the function of both Dcp1p and Dcp2p in decapping, we purified recombinant versions of these proteins from Escherichia coli and examined their properties [1].

High impact information on DCP1

• Subsequent recruitment of Dcp1p/Dcp2p to the complex appears to ensure rapid, deadenylation-independent decapping of the mRNA [2].
• PMR1 is uniformly distributed throughout the cytoplasm on polysomes and in lighter complexes and does not colocalize in cytoplasmic foci with Dcp1 [3].
• We show that Dcp1 binds to eIF4G and Pab1 as free proteins, as well as to the complex eIF4E-eIF4G-Pab1 [4].
• The eukaryotic mRNA decapping protein Dcp1 interacts physically and functionally with the eIF4F translation initiation complex [4].
• Dcp1 plays a key role in the mRNA decay process in Saccharomyces cerevisiae, cleaving off the 5' cap to leave an end susceptible to exonucleolytic degradation [4].

Biological context of DCP1

• To examine the relationship between the two DCP1-knockout phenotypes, we produced DCP1 point mutants that lack the ability to support the translation termination [5].
• These results suggest that direct or indirect interaction of Dcp1p with Dcp2p is required for the production of active decapping enzyme, perhaps in a process requiring the hydrolysis of a pyrophosphate bond [6].
• Based on alterations in mRNA decay rate from strains deficient in translation initiation, it has been proposed that the decapping rate is modulated by a competition between the cytoplasmic cap binding complex, which promotes translation initiation, and the decapping enzyme, Dcp1p [7].
• In order to test this model directly, we examined the functional interaction of Dcp1p and the cap binding protein, eukaryotic translation initiation factor 4E (eIF4E), in vitro [7].
• Characterization of Dcp1p activity in vitro indicated that the 7-methyl group of the cap structure contributes to the enzyme's substrate specificity [8].

Anatomical context of DCP1

• An mRNA decapping enzyme from ribosomes of Saccharomyces cerevisiae [9].
• This assay has been applied to the purified yeast decapping enzyme Dcp1 protein as well as crude yeast extracts and Xenopus oocyte extracts [10].

Physical interactions of DCP1

• The Dcp2p also coimmunoprecipitates with the DCP1 decapping enzyme and is required for the production of enzymatically active decapping enzyme [6].

Regulatory relationships of DCP1

• In addition, we demonstrate that in vivo a temperature-sensitive allele of eIF4E (cdc33-42) suppressed the decapping defect of a partial loss-of-function allele of DCP1 [7].
• We show that Edc3p can stimulate mRNA decapping of both unstable and stable mRNAs in yeast when the decapping enzyme is compromised by temperature-sensitive alleles of either the DCP1 or the DCP2 genes [11].

Other interactions of DCP1

• Further analysis has shown that PAT1 is allelic with mrt1-3, a mutation previously reported to affect decapping and to bypass suppress pab1Delta, as is also the case for dcp1, spb8, and mrt3 [12].
• These experiments indicated that eIF4E is an inhibitor of Dcp1p in vitro due to its ability to bind the 5' cap structure [7].
• We find here that Dcp1p can interact with the release factor eRF3p (Sup35p) in Saccharomyces cerevisiae [5].
• Using an in vitro decapping assay, we have identified a factor, Vps16p, that regulates the activity of the yeast decapping enzyme, Dcp1p [13].
• The role of Dhh1p in decapping appears to be direct, as Dhh1p physically interacts with several proteins involved in mRNA decapping including the decapping enzyme Dcp1p, as well as Lsm1p and Pat1p/Mrt1p, which function to enhance the decapping rate [14].

Analytical, diagnostic and therapeutic context of DCP1

• Evidence is presented here that Rpm2p interacts with Dcp2p, a subunit of mRNA decapping enzyme in the two-hybrid assay, and is enriched in cytoplasmic P bodies, the sites of mRNA degradation and storage in yeast and mammalian cells [15].

References