Coop functions as a corepressor of Pangolin and antagonizes Wingless signaling

Abstract

Supplemental material is available at http://www.genesdev.org.

Controlled levels of canonical Wnt signaling are required for neural crest migration

“…In the absence of Wnt signal Lef/Tcf acts as transcriptional repressors of Wnt target genes by forming a complex with several corepressors including myeloid translocation gene related-1 (Mtgr1) (Moore et al, 2008), corepressor of Pan (Coop) (Song et al, 2010), hydrogen peroxide-inducible clone (HIC5) (Ghogomu et al, 2006;Li et al, 2011) and the most intensively studied Groucho/transducin-like enhancer of split (Gro/TLE) repressor family Chen and Courey, 2000). Upon translocation of β-catenin to nucleus Lef/Tcf factors become converted into transcriptional activators and perform expression of the target genes (Daniels and Weis, 2005).…”

Wnt signaling through T-cell factor phosphorylation

“…In the simplest scenario, the function of β-catenin might be to provide a transcriptional activation domain to the TCF protein (which binds DNA via its high mobility group (HMG) domain) [40,115] (Figure 3). In another model, upon its binding to TCF proteins, β-catenin converts them into transcriptional activators by outcompeting transcriptional corepressors, such as Groucho, CtBP or HDACs [36,37,39,43,116]. Since both models presume the association of TCF with DNA, a phosphorylation event (such as that mediated by NLK or HIPK2) that causes the dissociation of TCF from the promoter would be predicted to inhibit both types of TCF-dependent gene activation [76,77,79,86].…”

“…enhancer of split) [27,28], CtBP [29,30], Kaiso [31][32][33], histone deacetylases (HDACs) and other factors, which maintain chromatin in the transcriptionally inactive state [34,35] and could mediate TCF-dependent transcriptional repression [28,[36][37][38][39]. The current model is that TCF proteins inhibit target genes when bound to Groucho/TLE corepressors, while association with β-catenin blocks these interactions and converts TCFs into transcriptional activators [1, 37,[40][41][42][43].…”

Gene Duplication, Lineage-Specific Expansion, and Subfunctionalization in the MADF-BESS Family Patterns theDrosophilaWing Hinge

“…Coop (Song et al 2010), a Pangolin-interacting protein and a member of the MADF-BESS family, has been shown to be a negative regulator of Wnt/Wg signaling, regulating Distalless at the D/V boundary. Our data on the other hand show that hng1 regulates Wg expression at the presumptive hinge region, with Coop, which is expressed in the wing hinge ( Figure 3K) playing a secondary role.…”

“…Adf1, a well-studied gene in the family, has been implicated as a transcriptional activator that contains a TAF-like binding motif (England et al 1992;Cutler et al 1998). Dorsal interacting protein 3 (Dip3) appears to be a co-activator in NF-kB/Twist function (Bhaskar and Courey 2002;Ratnaparkhi et al 2008) and also localizes to the heterochromatic chromocenter; while Co-repressor of Pangolin (Coop) is a negative regulator of Wg/Wnt signaling (Song et al 2010) and stwl is required for germ-cell development (Clark and McKearin 1996) and germ stem-cell maintenance (Maines et al 2007), acting as a repressor. The MADF domain in Stwl is implicated in chromatin remodeling and histone modification (Boyer et al 2002).…”