Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111.
Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts 02111.
J Neurosci. 2021 Apr 7;41(14):3082-3093. doi: 10.1523/JNEUROSCI.1074-20.2021. Epub 2021 Feb 23.
Reversible modification of AMPA receptors (AMPARs) with ubiquitin regulates receptor levels at synapses and controls synaptic strength. The conserved deubiquitinating enzyme (DUB) ubiquitin-specific protease-46 (USP-46) removes ubiquitin from AMPARs and protects them from degradation in both and mammals. Although DUBs are critical for diverse physiological processes, the mechanisms that regulate DUBs, especially in the nervous system, are not well understood. We and others previously showed that the WD40-repeat proteins WDR-48 and WDR-20 bind to and stimulate the catalytic activity of USP-46. Here, we identify an activity-dependent mechanism that regulates WDR-20 expression and show that WDR-20 works together with USP-46 and WDR-48 to promote surface levels of the AMPAR GLR-1. , , and loss-of-function mutants exhibit reduced levels of GLR-1 at the neuronal surface and corresponding defects in GLR-1-mediated behavior. Increased expression of WDR-20, but not WDR-48, is sufficient to increase GLR-1 surface levels in an -dependent manner. Loss of , , and function reduces the rate of local GLR-1 insertion in neurites, whereas overexpression of is sufficient to increase the rate of GLR-1 insertion. Genetic manipulations that chronically reduce or increase glutamate signaling result in reciprocal alterations in transcription and homeostatic compensatory changes in surface GLR-1 levels that are dependent on This study identifies as a novel activity-regulated gene that couples chronic changes in synaptic activity with increased local insertion and surface levels of GLR-1 via the DUB USP-46. Deubiquitinating enzymes (DUBs) are critical regulators of synapse development and function; however, the regulatory mechanisms that control their various physiological functions are not well understood. This study identifies a novel role for the DUB ubiquitin-specific protease-46 (USP-46) and its associated regulatory protein WD40-repeat protein-20 (WDR-20) in regulating local insertion of glutamate receptors into the neuronal cell surface. This work also identifies WDR-20 as an activity-regulated gene that couples chronic changes in synaptic activity with homeostatic compensatory increases in surface levels of GLR-1 via USP-46. Given that 35% of USP family DUBs associate with WDR proteins, understanding the mechanisms by which WDR proteins regulate USP-46 could have implications for a large number of DUBs in other cell types.
AMPA 受体（AMPAR）的泛素可逆修饰调节突触处的受体水平，并控制突触强度。保守的去泛素化酶（DUB）泛素特异性蛋白酶 46（USP-46）从 AMPAR 上去除泛素，防止它们在 和哺乳动物中降解。尽管 DUB 对于各种生理过程至关重要，但调节 DUB 的机制，特别是在神经系统中，尚不清楚。我们和其他人之前曾表明，WD40 重复蛋白 WDR-48 和 WDR-20 与 USP-46 结合并刺激其催化活性。在这里，我们确定了一种调节 WDR-20 表达的活性依赖性机制，并表明 WDR-20 与 USP-46 和 WDR-48 一起工作，以促进 AMPAR GLR-1 的表面水平。 ， ， 和 功能丧失突变体表现出神经元表面 GLR-1 水平降低，以及 GLR-1 介导的行为缺陷。以 依赖性方式增加 WDR-20 的表达，但不是 WDR-48 的表达，足以增加 GLR-1 的表面水平。 ， ， 和 功能丧失会降低神经突中局部 GLR-1 插入的速率，而过表达 则足以增加 GLR-1 插入的速率。慢性降低或增加谷氨酸信号转导的遗传操作导致 转录的正反变化以及依赖于 的 GLR-1 表面水平的同源补偿性变化。本研究确定 作为一种新的活性调节基因，通过 DUB USP-46 将突触活动的慢性变化与 GLR-1 的局部插入和表面水平的增加联系起来。去泛素化酶（DUB）是突触发育和功能的关键调节剂；然而，控制其各种生理功能的调节机制尚不清楚。本研究确定了 DUB 泛素特异性蛋白酶 46（USP-46）及其相关调节蛋白 WD40 重复蛋白-20（WDR-20）在调节谷氨酸受体局部插入神经元细胞膜表面中的新作用。这项工作还确定了 WDR-20 是一种活性调节基因，通过 USP-46 将突触活动的慢性变化与 GLR-1 表面水平的同源补偿性增加联系起来。鉴于 35%的 USP 家族 DUB 与 WDR 蛋白相关，了解 WDR 蛋白调节 USP-46 的机制可能对其他细胞类型中的大量 DUB 具有重要意义。
