Affinity Chromatography of Regulatory Subunits of Protein Phosphatase-1

1996 ◽  
Vol 325 (1) ◽  
pp. 82-90 ◽  
Author(s):  
Sumin Zhao ◽  
Wenle Xia ◽  
Ernest Y.C. Lee
Keyword(s):  
Affinity Chromatography ◽  
Protein Phosphatase ◽  
Protein Phosphatase 1 ◽  
Regulatory Subunits

Protein Phosphatase-1 Complex Disassembly by p97 is Initiated through Multivalent Recognition of Catalytic and Regulatory Subunits by the p97 SEP-domain Adapters

2020 ◽  
Vol 432 (23) ◽  
pp. 6061-6074
Author(s):  
Matthias Kracht ◽  
Johannes van den Boom ◽  
Jonas Seiler ◽  
Alexander Kröning ◽  
Farnusch Kaschani ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Protein Phosphatase 1 ◽  
Regulatory Subunits

Transcriptional control by chromosome-associated protein phosphatase-1

2005 ◽  
Vol 33 (6) ◽  
pp. 1444-1446 ◽  
Author(s):  
D. Bennett
Keyword(s):  
Gene Expression ◽  
Protein Phosphatase ◽  
Transcriptional Control ◽  
Regulation Of Gene Expression ◽  
Polytene Chromosomes ◽  
Protein Phosphatase 1 ◽  
Environmental Cues ◽  
Spatial And Temporal Patterns ◽  
Regulatory Subunits ◽  
Chromosomal Loci

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.

scholarly journals Association of Brain Protein Phosphatase 1 with Cytoskeletal Targeting/Regulatory Subunits

2002 ◽  
Vol 69 (3) ◽  
pp. 920-929 ◽  
Author(s):  
Roger J. Colbran ◽  
Martha A. Bass ◽  
R. Blair McNeill ◽  
Mathieu Bollen ◽  
Sumin Zhao ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Protein Phosphatase 1 ◽  
Brain Protein ◽  
Regulatory Subunits

scholarly journals Glc7/Protein Phosphatase 1 Regulatory Subunits Can Oppose the Ipl1/Aurora Protein Kinase by Redistributing Glc7

2006 ◽  
Vol 26 (7) ◽  
pp. 2648-2660 ◽  
Author(s):  
Benjamin A. Pinsky ◽  
Chitra V. Kotwaliwale ◽  
Sean Y. Tatsutani ◽  
Christopher A. Breed ◽  
Sue Biggins
Keyword(s):  
Protein Kinase ◽  
Chromosome Segregation ◽  
Protein Phosphatase ◽  
Kinase Activity ◽  
Budding Yeast ◽  
Protein Phosphatase 1 ◽  
Wild Type ◽  
Regulatory Subunits ◽  
The Relationship ◽  
Mutant Cells

ABSTRACT Faithful chromosome segregation depends on the opposing activities of the budding yeast Glc7/PP1 protein phosphatase and Ipl1/Aurora protein kinase. We explored the relationship between Glc7 and Ipl1 and found that the phosphorylation of the Ipl1 substrate, Dam1, was altered by decreased Glc7 activity, whereas Ipl1 levels, localization, and kinase activity were not. These data strongly suggest that Glc7 ensures accurate chromosome segregation by dephosphorylating Ipl1 targets rather than regulating the Ipl1 kinase. To identify potential Glc7 and Ipl1 substrates, we isolated ipl1-321 dosage suppressors. Seven genes (SDS22, BUD14, GIP3, GIP4, SOL1, SOL2, and PEX31) encode newly identified ipl1 dosage suppressors, and all 10 suppressors encode proteins that physically interact with Glc7. The overexpression of the Gip3 and Gip4 suppressors altered Glc7 localization, indicating they are previously unidentified Glc7 regulatory subunits. In addition, the overexpression of Gip3 and Gip4 from the galactose promoter restored Dam1 phosphorylation in ipl1-321 mutant cells and caused wild-type cells to arrest in metaphase with unsegregated chromosomes, suggesting that Gip3 and Gip4 overexpression impairs Glc7's mitotic functions. We therefore propose that the overexpression of Glc7 regulatory subunits can titrate Glc7 away from relevant Ipl1 targets and thereby suppress ipl1-321 cells by restoring the balance of phosphatase/kinase activity.

scholarly journals Colocalization Analysis of PPP1 Isoforms and Two Novel Targeting Subunits in Breast Carcinoma

2008 ◽  
Vol 14 (S3) ◽  
pp. 134-136
Author(s):  
C. Sousa ◽  
A.P. Vintém ◽  
M. Fardilha ◽  
O. da Cruz e Silva ◽  
E. da Cruz e Silva
Keyword(s):  
Protein Phosphatase ◽  
Cellular Localization ◽  
Carcinoma Cells ◽  
Protein Phosphatase 1 ◽  
The Novel ◽  
Regulatory Subunits ◽  
Novel Proteins ◽  
Fluorescent Microscope ◽  
Gfp Fusion Protein ◽  
Overlap Coefficient

Protein phosphatase 1 (PPP1) is the PPP most ubiquitous and each isoform interact with regulatory subunits that may be responsible for their subcellular localization. We identified PPP1R15B, C1ORF71 as novel regulators and the aim of this study was their further characterization in carcinoma cells. We analysed localization of each regulator in MDA-MB-468 cells and we transfected with constructs that we made with each as a GFP-fusion protein. For PPP1 cellular localization we used specific antibodies for each isoform. We observed the cells under a fluorescent microscope and LSM and we quantified co-localization. We found a high overlap coefficient of both the novel proteins with PPP1alpha and PPP1gamma1. We propose a model in which PPP1 regulator interacts with one or two regulatory subunits that may be used as target for therapeutic strategies.

Protein phosphatase 1 – targeted in many directions

2002 ◽  
Vol 115 (2) ◽  
pp. 241-256 ◽  
Author(s):  
Patricia T. W. Cohen
Keyword(s):  
Protein Phosphatase ◽  
Protein Phosphatase 1 ◽  
Binding Motif ◽  
Cellular Functions ◽  
Regulatory Subunits ◽  
Specific Location ◽  
Hydrophobic Groove ◽  
Intracellular Signals ◽  
Small Hydrophobic ◽  
Rvxf Motif

Protein phosphatase 1 (PP1) is a major eukaryotic protein serine/threonine phosphatase that regulates an enormous variety of cellular functions through the interaction of its catalytic subunit (PP1c) with over fifty different established or putative regulatory subunits. Most of these target PP1c to specific subcellular locations and interact with a small hydrophobic groove on the surface of PP1c through a short conserved binding motif – the RVxF motif – which is often preceded by further basic residues. Weaker interactions may subsequently enhance binding and modulate PP1 activity/specificity in a variety of ways. Several putative targeting subunits do not possess an RVxF motif but nevertheless interact with the same region of PP1c. In addition, several ‘modulator’ proteins bind to PP1c but do not possess a domain targeting them to a specific location. Most are potent inhibitors of PP1c and possess at least two sites for interaction with PP1c, one of which is identical or similar to the RVxF motif.Regulation of PP1c in response to extracellular and intracellular signals occurs mostly through changes in the levels, conformation or phosphorylation status of targeting subunits. Understanding of the mode of action of PP1c complexes may facilitate development of drugs that target particular PP1c complexes and thereby modulate the phosphorylation state of a very limited subset of proteins.

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