Kinesin-14 manufacturer activity of PP1 (Kim et al., 2003). We then examined if acetylated histone could also recognize this region, acquiring that deletion of a.a. 443-455 of PNUTS abolished its interaction with acetylated histone H3 (Figure 6E), suggesting that the inhibitory part of PNUTS, mediated by motif a.a. 443-455, is attenuated within the presence of acetylated histone, top to activation of PP1 enzymatic activity. Consistently, acetylated, but not methylated, histone peptides particularly rescued PP1 activity from PNUTS inhibition (Figure 6F). PP1 has been reported to dephosphorylate the Carboxyl-Terminal Domain (CTD domain) of RNA polymerase II at Ser5, which can be accumulated at promoter regions of target genes (Komarnitsky et al., 2000; Washington et al., 2002). A recent study showed that depletion of PNUTS in Drosophila outcomes in worldwide hyperphosphorylation of RNA Pol II Ser5, leading to worldwide transcription pause and development defect (Ciurciu et al., 2013). For that reason, we subsequent tested if PNUTS/PP1 regulates phosphorylation of RNA Pol II Ser5, obtaining that knockdown of PNUTS led towards the hyperphosphorylation of RNA Pol II Ser5 (Figures S6E and S6F). We then investigated the functional roles of PNUTS-acetylated histone interaction in regulating the status of RNA Pol II Ser5 phosphorylation within the presence of a p300 inhibitor, C646, which eliminated the histone acetylation as represented by H3K18ac (Figures 6G, S6G and S6H). Our information indicates that CCL21-triggered recruitment of PNUTS and PP1 for the promoters of GLI2 target genes was not affected by p300 inhibitor (Figures 6G, S6G and S6H) plus the levels of Pol II Ser5 phosphorylation on these promoters were decreased uponCell. Author manuscript; accessible in PMC 2015 November 20.Xing et al.PageCCL21 treatment (Figures 6G, S6G and S6H). Nonetheless, the CCL21-induced hypophosphorylation of RNA Pol II Ser5 was abolished inside the presence with the p300 inhibitor (Figures 6G, S6G and S6H), suggesting that histone acetylation-dependent PP1 activity modulates RNA Pol II Ser5 phosphorylation level at gene promoter regions. Taken together, the data demonstrate the essential roles of BCAR4, by way of its interaction with SNIP1 and PNUTS, in linking signal-induced acetylation of histone to common transcription machinery through the activation from the GLI2 target genes in breast cancer cells. BCAR4 as a Prospective Therapeutic Target for Breast Cancer Metastasis To further confirm the functional connection in between BCAR4 and breast cancer metastasis, we performed functional rescue experiments in which we depleted BCAR4 by LNA followed by overexpression in MDA-MB-231 cells of either LNA-resistant full-length BCAR4 or truncated mutants defective for SNIP1 or PNUTS binding (see Figures 2F-2H and Figure S7A). In cell motility assays, knockdown of BCAR4 decreased migration and invasion of MDA-MB-231 cells, which might be rescued by re-introduction of full-length, but neither 212-311 nor 968-1087 truncated kind of BCAR4 (Figures S7B and S7C), despite the fact that the expression of full-length BCAR4 and truncated types was equal (Figure S7A), and cell PDE3 Source proliferation was not altered (information not shown). Knockdown of BCAR4 also curtailed the expression of GLI2 target genes and re-introduction of full-length BCAR4, but neither 212-311 nor 968-1087 truncated types of BCAR4 was in a position to robustly rescue the induction of those genes (Figures S7D and S7E). Regularly, knockdown of BCAR4 abolished CCL21-induced SNIP1 and PNUTS interaction, whilst re-introdu.