High impact information on Ide

• The IDE levels in the cell lines are particularly high, at least 10-fold greater than in the adult fly [1].
• We now demonstrate that the IDE is present in other Drosophila cell lines and in the embryo, the larvae, the pupae, and adult tissues of the fruit fly [1].
• The particular pattern of developmental regulation suggests that the IDE plays a specific and critical role in the later stages of the life cycle of the fly [1].
• Vectors containing wild type or mutant IDE genes were transfected into COS cells, and the enzymes were analyzed for insulin degradation, insulin cross-linking, and zinc binding [2].
• Affinity purified endosomal acidic insulinase displayed a pH optimum of 4-5.5, a lack of inhibition by EDTA and N-ethylmaleimide, and a partial metal-ion requirement (for Mn2+) all of which distinguished it from IDE [3].

Biological context of Ide

• The gene for the dIDE has been mapped to chromosome 3L (77B) [4].
• On the basis of enzymatic properties and substrate specificity, this enzyme was identified as the Drosophila homolog of the mammalian insulin-degrading enzyme (IDE) [4].
• Insulin-degrading enzyme (IDE) is a sulfhydryl-dependent metalloproteinase with a zinc binding site unique to a new class of proteinases [5].
• Further, the level of the IDE is developmentally regulated, being barely detectable in the embryo but elevated approximately 5-fold in the larvae and pupae and approximately 10-fold in the adult fly [1].
• The lysosomotropic agents chloroquine and NH4Cl did not affect the increase in insulin degradation produced by transfection with dIDE, indicating that the lysosomal and IDE-mediated pathways of insulin degradation are independent [6].

Associations of Ide with chemical compounds

• The Drosophila IDE activity, like the mammalian enzymes, is inhibited by bacitracin and sulfhydryl-specific reagents [7].
• Similarly, the Drosophila IDE activity is insensitive to glutathione as well as protease inhibitors such as aprotinin and leupeptin [7].
• This cysteine has been postulated to mediate the differential sensitivity of IDE and protease III to cysteine protease inhibitors and chelators [8].

Analytical, diagnostic and therapeutic context of Ide

• Northern blot analysis indicates that the dIDE is translated from a 3.6-kilobase transcript similar in size to one of the two human IDE transcripts [4].
• A small but detectable presence of IDE in particulate nuclear (N) and large granule (ML) fractions was observed by differential centrifugation [3].
• In purified endosomal fractions insulin was actively degraded at acid pH and IDE was undetectable as evaluated by immunoblotting, immunoprecipitation, or chemical cross-linking procedures [3].

References