Interactomic analysis of REST/NRSF and implications of its functional links with the transcription suppressor TRIM28 during neuronal differentiation

Abstract

RE-1 silencing transcription factor (REST) is a transcriptional repressor that regulates gene expression by binding to repressor element 1. However, despite its critical function in physiology, little is known about its interaction proteins. Here we identified 204 REST-interacting proteins using affinity purification and mass spectrometry. The interactome included proteins associated with mRNA processing/splicing, chromatin organization, and transcription. The interactions of these REST-interacting proteins, which included TRIM28, were confirmed by co-immunoprecipitation and immunocytochemistry, respectively. Gene Ontology (GO) analysis revealed that neuronal differentiation-related GO terms were enriched among target genes that were co-regulated by REST and TRIM28, while the level of CTNND2 was increased by the knockdown of REST and TRIM28. Consistently, the level of CTNND2 increased while those of REST and TRIM28 decreased during neuronal differentiation in the primary neurons, suggesting that CTNND2 expression may be co-regulated by both. Furthermore, neurite outgrowth was increased by depletion of REST or TRIM28, implying that reduction of both REST and TRIM28 could promote neuronal differentiation via induction of CTNND2 expression. In conclusion, our study of REST reveals novel interacting proteins which could be a valuable resource for investigating unidentified functions of REST and also suggested functional links between REST and TRIM28 during neuronal development.

Loss of zebrafish ctnnd2b results in disorganised forebrain neuron clusters

“…Recently CTNND2 has shown to be a target gene of REST and CoREST (Abrajano et al, 2009), transcription factors which are thought to modulate neuronal subtype specification (Lee et al, 2016). Our study supports a role for ∂ -catenin in subtype specification.…”

“…During development of the nervous system, the encoded protein ∂ -catenin appears to be involved in various neurodevelopment processes. These include neuronal differentiation (Lee et al, 2016), synaptic dysfunction (Israely et al, 2004), dendritic branching, spine morphogenesis (Kim et al, 2008), and maintenance of mature dendrites and dendritic spines (Matter et al, 2009) (Gilbert and Man, 2016). Homozygous mice expressing the GFP-tagged N-terminal domain of CTNND2 show spatial learning difficulties and abnormal fear conditioning (Israely et al, 2004), possibly due to abnormalities in dendritic arbour maintenance (Matter et al, 2009), suggesting that loss of ∂ -catenin affects behaviour.…”

Molecular profiling stratifies diverse phenotypes of treatment-refractory metastatic castration-resistant prostate cancer

“…Interestingly, we observed REST species with our REST C-terminus antibody at both approximately 120 KDa and approximately 200 KDa in PDX lysates from ARPC, ARLPC, and DNPC. Full-length REST protein is predicted to be 116 KDa but can be O-glycosylated and readily detected at approximately 200 KDa (21,22). Additionally, the REST transcript has multiple splice variants that produce truncated proteins (23).…”

TRIM28 haploinsufficiency predisposes to Wilms tumor

“…The additional observation of TRIM28 LOH in the tumors provides evidence that in Wilms tumor development, TRIM28 functions as a classical tumor suppressor gene. Several cancer predisposing genes are known to interact with TRIM28 , including TP53 , the recently identified Wilms tumor predisposition gene REST and AMER1 , a gene frequently mutated somatically in Wilms tumors . In individual 3, a previously reported somatic nonsense mutation in AMER1 was identified, in addition to two mutations in DICER1 .…”