Systematic Analysis of the Physiological Importance of Deubiquitinating Enzymes

Abstract

Deubiquitinating enzymes (DUBs) are proteases that control the post-translational modification of proteins by ubiquitin and in turn regulate diverse cellular pathways. Despite a growing understanding of DUB biology at the structural and molecular level, little is known about the physiological importance of most DUBs. Here, we systematically identify DUBs encoded by the genome of Drosophila melanogaster and examine their physiological importance in vivo. Through domain analyses we uncovered 41 Drosophila DUBs, most of which have human orthologues. Systematic knockdown of the vast majority of DUBs throughout the fly or in specific cell types had dramatic consequences for Drosophila development, adult motility or longevity. Specific DUB subclasses proved to be particularly necessary during development, while others were important in adults. Several DUBs were indispensable in neurons or glial cells during developmental stages; knockdown of others perturbed the homeostasis of ubiquitinated proteins in adult flies, or had adverse effects on wing positioning as a result of neuronal requirements. We demonstrate the physiological significance of the DUB family of enzymes in intact animals, find that there is little functional redundancy among members of this family of proteases, and provide insight for future investigations to understand DUB biology at the molecular, cellular and organismal levels.

Deubiquitylases From Genes to Organism

“…Figure 1. A systematic study of the 41 Drosophila DUBs has revealed key roles in development, adult motility, and longevity (260), while a morpholino-based functional screen has identified 57 DUBs that play key roles in early development of zebrafish (259).…”

Mechanisms promoting and inhibiting the process of proteasomal degradation of cells

“…This system is based on the 26S proteasomethe dynamic, complex proteolytic subunit with a molecular weight of 1500 to 2000 kD, which in eukaryotes is the basis nonlysosomal proteolysis. The function of this intracellular protease is recognition and degradation of the ubiquitin-tagged proteins [2,24].…”

“…przebieg cyklu komórkowego, różnicowanie, wewnątrzkomórkowe przekazywanie sygnałów, mechanizmy naprawcze DNA. Nadzoruje również proces jej programowanej śmierci [2,3].…”

Should Deubiquitinating Enzymes be Targeted for Therapy?

“…Although this large number would suggest functional redundancy, substantial evidence indicates that this is not the case [9][10][11][12][13][14][15]. Because of tissue-and substrate-specificity, DUBs are in fact attractive therapeutic targets.…”

“…We should be mindful of potential side effects from inhibiting or activating DUB's enzymatic properties. We recently showed that RNA-interference-mediated knockdown of most DUBs encoded by the model organism Drosophila melanogaster had negative physiological consequences during development or in adults [13]. Similarly, mutations or knockouts of several DUBs in mice, including USP14 [20][21][22][23][24][25] and USP7 [26][27][28], caused negative outcomes in the entire organism or in specific organ systems [7].…”