Systematic Analysis of the Physiological Importance of Deubiquitinating Enzymes

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.去泛素化酶（Deubiquitinating enzymes, DUBs）是一类通过调控蛋白质的泛素化翻译后修饰，进而调控多种细胞通路的蛋白酶。尽管目前在结构与分子层面对DUB的生物学特性已有愈发深入的认知，但多数DUB的生理重要性仍未得到充分阐明。本研究系统性鉴定了黑腹果蝇（Drosophila melanogaster）基因组编码的全部去泛素化酶，并在活体水平考察了它们的生理重要性。通过结构域分析，我们共鉴定出41个黑腹果蝇去泛素化酶，其中绝大多数拥有人类同源基因。对果蝇全身或特定细胞类型中的绝大多数去泛素化酶进行系统性敲低，会对果蝇的发育、成虫运动能力及寿命产生显著影响。特定的去泛素化酶亚家族在发育过程中尤为关键，而其他亚家族则在成虫阶段发挥重要功能。部分去泛素化酶在发育阶段的神经元或神经胶质细胞中不可或缺；敲低其他去泛素化酶则会扰乱成虫体内泛素化蛋白的稳态，或因神经元功能异常导致翅膀定位缺陷。本研究证实了去泛素化酶家族在完整动物个体中的生理重要性，发现该蛋白酶家族成员间几乎不存在功能冗余，并为后续从分子、细胞乃至个体水平解析去泛素化酶的生物学特性提供了研究思路。