A kinome-wide RNAi screen identifies ERK2 as a druggable regulator of Shank3 stability

Abstract

Neurons are sensitive to changes in the dosage of many genes, especially those regulating synaptic functions. Haploinsufficiency of SHANK3 causes Phelan-McDermid syndrome and autism, whereas duplication of the same gene leads to SHANK3 duplication syndrome, a disorder characterized by neuropsychiatric phenotypes including hyperactivity and bipolar disorder as well as epilepsy. We recently demonstrated the functional modularity of Shank3, which suggests that normalizing levels of Shank3 itself might be more fruitful than correcting pathways that function downstream of it for treatment of disorders caused by alterations in SHANK3 dosage. To identify upstream regulators of Shank3 abundance, we performed a kinome-wide siRNA screen and identified multiple kinases that potentially regulate Shank3 protein stability. Interestingly, we discovered that several kinases in the MEK/ERK2 pathway destabilize Shank3 and that genetic deletion and pharmacological inhibition of ERK2 increases Shank3 abundance in vivo. Mechanistically, we show that ERK2 binds Shank3 and phosphorylates it at three residues to promote its poly-ubiquitination-dependent degradation. Together, our findings uncover a druggable pathway as a potential therapeutic target for disorders with reduced SHANK3 dosage, provide a rich resource for studying Shank3 regulation, and demonstrate the feasibility of this approach for identifying regulators of dosage-sensitive genes.

Using Zebrafish to Model Autism Spectrum Disorder: A Comparison of ASD Risk Genes Between Zebrafish and Their Mammalian Counterparts

“…Studies in mice have shown that Shank3 is essential for proper synaptic function and mutations in this gene lead to impaired motor coordination, repetitive behavior and altered social interactions ( Uchino and Waga, 2015 ; Amal et al, 2018 ; Wang et al, 2019 ). At least five mutant Shank3 lines altering different regions of the protein have been created in mice ( Jiang and Ehlers, 2013 ).…”

Autism associatedSHANK3missense point mutations impact conformational fluctuations and protein turnover at synapses

“…As SHANK3 is critically involved in regulating synaptic structure and function, neurons are sensitive to altered gene dosage, which has been pointed out by several studies (Bozdagi et al, 2010; Durand et al, 2007; Wang, Adamski, et al, 2019; Yi et al, 2016). Of note, albeit both mutations are located within the SPN domain, they had distinct effects on SHANK3 folding and residing time as well as localization at the synapse, suggesting that each point mutation might cause synaptic dysfunction by different mechanisms.…”

Shank3 Exons 14–16 Deletion in Glutamatergic Neurons Leads to Social and Repetitive Behavioral Deficits Associated With Increased Cortical Layer 2/3 Neuronal Excitability

“…Mutations in the SHANK3 gene have been associated with various brain disorders, including autism spectrum disorders (ASD), Phelan-McDermid Syndrome (PMS), schizophrenia, intellectual disability, and mania (Wilson et al, 2003; Gauthier et al, 2010; Bonaglia et al, 2011; Hamdan et al, 2011; Phelan and McDermid, 2012; Boccuto et al, 2013; Han et al, 2013; Guilmatre et al, 2014; Leblond et al, 2014; Cochoy et al, 2015). Mechanisms underlying the development of Shank3-related brain dysfunctions have been suggested through studies of a large number of Shank3 -mutant mice (Bozdagi et al, 2010; Peca et al, 2011; Wang X. et al, 2011; Yang et al, 2012; Han et al, 2013; Jiang and Ehlers, 2013; Kouser et al, 2013; Duffney et al, 2015; Lee et al, 2015; Sala et al, 2015; Speed et al, 2015; Jaramillo et al, 2016, 2017; Mei et al, 2016; Wang et al, 2016, 2019a,b; Zhou et al, 2016; Monteiro and Feng, 2017; Vicidomini et al, 2017; Bey et al, 2018; Drapeau et al, 2018; Qin et al, 2018; Yoo et al, 2018).…”