REST/NRSF-Interacting LIM Domain Protein, a Putative Nuclear Translocation Receptor

Abstract

The transcriptional repressor REST/NRSF (RE-1 silencing transcription factor/neuron-restrictive silencer factor) and the transcriptional regulator REST4 share an N-terminal zinc finger domain structure involved in nuclear targeting. Using this domain as bait in a yeast two-hybrid screen, a novel protein that contains three LIM domains, putative nuclear localization sequences, protein kinase A phosphorylation sites, and a CAAX prenylation motif was isolated. This protein, which is localized around the nucleus, is involved in determining the nuclear localization of REST4 and REST/NRSF. We propose the name RILP, for REST/NRSF-interacting LIM domain protein, to label this novel protein. RILP appears to serve as a nuclear receptor for REST/NRSF, REST4, and possibly other transcription factors.One of the major transcription factors regulating the expression of neuronal genes is the repressor element 1 (RE-1) silencing transcription factor (REST) (7), also called the neuron-restrictive silencer factor (NRSF) (24), which binds to a 21-bp DNA regulatory element, RE-1, also known as the neuron-restrictive silencer element (NRSE). REST/NRSF is a modular protein containing an N-terminal repression domain, a DNA binding domain composed of eight consecutive Cys 2 -His 2 zinc fingers, a highly basic region, and a C-terminal repression domain containing a single Cys 2 -His 2 zinc finger motif. The mechanism whereby REST/NRSF represses gene transcription has not been fully elucidated. It has been reported that the silencing activity of REST/NRSF correlates with the recruitment of the corepressor mSin3 to a site near the N terminus, which then forms a complex with histone deacetylase (6,13,17). This results in the deacetylation of nearby histones, compaction of the DNA, and loss of transcriptional activity. In addition, a novel protein called Co-REST (2) binds to the C-terminal region of REST/NRSF and helps to repress gene transcription by an unknown mechanism. Co-REST appears to act independently of the action of histone deacetylase. REST/NRSF thus has a bipartite mechanism for repression of gene expression.Several variants of REST/NRSF mRNA, derived by alternative splicing of REST/NRSF pre-mRNA, are expressed in mature neurons of the adult rat brain, albeit at low levels (19). They encode protein isoforms with four or five zinc finger motifs. Two of these splice variants have an insertion of either 16 nucleotides (REST4) or 28 nucleotides (REST5) in the region of the gene encoding a spacer between zinc fingers 5 and 6 and produce truncated proteins containing only five of the nine zinc finger domains found in full-length REST/NRSF.We have previously reported that REST4 acts as a dominant negative and blocks the ability of REST/NRSF to bind to DNA (25). We reported that REST4 could derepress choline acetyltransferase gene expression in a model PC12 cell line (A126.1B2), presumably by blocking the repressor activity of REST/NRSF. We proposed that REST4 acts as a modulator or "antisilencer" of REST/NRSF transcriptional repression....

Zebrafish Prickle1b mediates facial branchiomotor neuron migration via a farnesylation-dependent nuclear activity

“…Pk1b contains one PET domain, three LIM domains, three nuclear localization signals (NLSs) and a farnesylation motif (CaaX), as has been reported previously for other Pk homologs (Jenny et al, 2003;Shimojo and Hersh, 2003) (Fig. 1A).…”

“…Previous research has shown that human PK1 functions at the nuclear membrane to regulate nuclear translocation of the transcriptional silencer REST (Shimojo and Hersh, 2003;Shimojo and Hersh, 2006). We 2127 RESEARCH ARTICLE Pk1b farnesylation during FBMN migration hypothesized that this role is conserved in zebrafish Pk1b, and therefore first sought to determine whether REST functions during FBMN migration.…”

“…1A). Cell culture studies have demonstrated that the CaaX and NLS motifs are important for nuclear localization (Shimojo and Hersh, 2003;Shimojo and Hersh, 2006); however, the importance of these domains has not been studied extensively in vivo.…”

“…REST plays numerous roles in many cell types, including repression of neuronal genes in non-neuronal cells and regulation of the terminal differentiation of neurons (reviewed by Ballas and Mandel, 2005;Qureshi and Mehler, 2009). Interaction with PK1 influences REST nuclear localization and therefore its repressive ability in cell culture (Shimojo and Hersh, 2003;Shimojo and Hersh, 2006;Bassuk et al, 2008). Recently, a mutation in PK1 that reduces binding to REST has been linked to the autosomal recessive syndrome progressive myoclonus epilepsy with ataxia (PME) (Bassuk et al, 2008).…”

“…The human PRICKLE1 (PK1) homolog has been demonstrated to interact directly with the transcriptional repressor RE1-silencing transcription factor (REST) (Shimojo and Hersh, 2003;Shimojo and Hersh, 2006). REST plays numerous roles in many cell types, including repression of neuronal genes in non-neuronal cells and regulation of the terminal differentiation of neurons (reviewed by Ballas and Mandel, 2005;Qureshi and Mehler, 2009).…”