Transcriptional control by chromosome-associated protein phosphatase-1

Abstract

Tight regulation of gene expression is critical for cells to respond normally to physiological and environmental cues and to allow cell specialization. Reversible phosphorylation of key structural and regulatory proteins, from histones to the transcriptional machinery, is acknowledged to be an important mechanism of regulating spatial and temporal patterns of gene expression. PP1 (protein phosphatase-1), a major class of serine/ threonine protein phosphatase, is found at many sites on Drosophila polytene chromosomes where it is involved in controlling gene expression and chromatin structure. PP1 is targeted to different chromosomal loci through interaction with a variety of different regulatory subunits, which modify PP1's activity towards specific substrates. This mini-review gives an overview of known chromosome-associated PP1 complexes, their role in transcriptional control and the prospects for future analysis.

CCDC6 represses CREB1 activity by recruiting histone deacetylase 1 and protein phosphatase 1

“…To further show that CCDC6 expression is able to reduce the phosphorylation at Ser133 of CREB1 protein, the endogenous CCDC6 gene expression was transiently silenced transfecting B-CPAP cells with small-interfering RNAs (CCDC6i-345). As shown in Figure 3a (right panel), silencing of CCDC6 gene expression increased the phosphorylation status of CREB1, in comparison with the same cells treated with CCDC6 physically interacts with PP1 on the AREG promoter PP1, PP2A, and PP2B, belonging to the PPP family of Ser/Thr protein phosphatases, participate in regulating many important physiological processes, such as cell cycle control and regulation of cell growth and division regulation (Klumpp and Krieglstein, 2002;Terrak et al, 2004;Bennett, 2005;Trinkle-Mulcahy and Lamond, 2006;Han et al, 2007;Wang et al, 2008;Virshup and Shenolikar, 2009). It has also been reported that CREB1 is inactivated by PP1 through dephosphorylation at Ser133 (Hagiwara et al, 1992).…”

Protein Phosphatase 1 Regulates the Histone Code for Long-Term Memory

“…In vitro, PP1 is an important regulator of transcriptional and translational events such as mRNA processing, splicing, and translation initiation in several cell types (Bennett, 2005;Mansuy and Shenolikar, 2006;Moorhead et al, 2007). On a subcellular level, it is abundant in the nucleus in which it forms distinct multimeric holoenzymes with specific targeting partners and thereby regulates substrates involved in nuclear processes (Bennett, 2005). In yeast, Caenorhabditis elegans, and Xenopus during mitosis, PP1 controls histone 3 (H3) dephosphorylation and can thereby reverse the action of Aurora protein kinases (Hsu et al, 2000;Murnion et al, 2001).…”

Biophysical Analysis of the N-Terminal Domain from the Human Protein Phosphatase 1 Nuclear Targeting Subunit PNUTS Suggests an Extended Transcription Factor TFIIS-Like Fold

“…Human PNUTS (PP1 Nuclear Targeting Protein) is a Protein Phosphatase 1 (PP1) binding protein with critical functions in the response to cellular stresses, including DNA damage, and the regulation of RNA-polymerase II -mediated gene expression [1][2][3][4][5]. It forms a ternary complex with PP1, Tox4 and WDR82 that targets PP1 to the nucleus [3][4][5][6][7][8][9][10], and further interacts with the tumour suppressor phosphatase and tensin homolog PTEN [11].…”

“…It forms a ternary complex with PP1, Tox4 and WDR82 that targets PP1 to the nucleus [3][4][5][6][7][8][9][10], and further interacts with the tumour suppressor phosphatase and tensin homolog PTEN [11].…”