Cancerous inhibitor of protein phosphatase 2A (CIP2A) modifies energy metabolism via 5′ AMP-activated protein kinase signalling in malignant cells

2019 ◽  
Vol 476 (15) ◽  
pp. 2255-2269 ◽  
Author(s):  
James A. Austin ◽  
Rosalind E. Jenkins ◽  
Gemma M. Austin ◽  
Mark A. Glenn ◽  
Karen Dunn ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Protein Kinase ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
K562 Cells ◽  
Spectrometric Analysis ◽  
Malignant Cells ◽  
Phosphatase 2A ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

Abstract Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an adverse biomarker across many malignancies. Using K562 cells engineered to have high or low CIP2A expression, we show that high CIP2A levels significantly bias cellular energy production towards oxidative phosphorylation (OXPHOS) rather than glycolysis. Mass spectrometric analysis of CIP2A interactors and isobaric tagging for relative and absolute protein quantitation (ITRAQ) experiments identified many associated proteins, several of which co-vary with CIP2A level. Many of these CIP2A associating and co-varying proteins are involved in energy metabolism including OXPHOS, or in 5′ AMP-activated protein kinase (AMPK) signalling, and manipulating AMPK activity mimics the effects of low/high CIP2A on OXPHOS. These effects are dependent on the availability of nutrients, driven by metabolic changes caused by CIP2A. CIP2A level did not affect starvation-induced AMPK phosphorylation of Unc-51 autophagy activating kinase 1 (ULK-1) at Ser555, but autophagy activity correlated with an increase in AMPK activity, to suggest that some AMPK processes are uncoupled by CIP2A, likely via its inhibition of protein phosphatase 2A (PP2A). The data demonstrate that AMPK mediates this novel CIP2A effect on energy generation in malignant cells.

scholarly journals Activation of Protein Phosphatase 2A by Palmitate Inhibits AMP-activated Protein Kinase

2007 ◽  
Vol 282 (13) ◽  
pp. 9777-9788 ◽  
Author(s):  
Yong Wu ◽  
Ping Song ◽  
Jian Xu ◽  
Miao Zhang ◽  
Ming-Hui Zou
Keyword(s):  
Protein Kinase ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Phosphatase 2A ◽  
Amp Activated Protein Kinase

scholarly journals Withdrawal: Activation of protein phosphatase 2A by palmitate inhibits AMP-activated protein kinase.

2019 ◽  
Vol 294 (27) ◽  
pp. 10741-10741
Author(s):  
Yong Wu ◽  
Ping Song ◽  
Jian Xu ◽  
Miao Zhang ◽  
Ming-Hui Zou
Keyword(s):  
Protein Kinase ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Phosphatase 2A ◽  
Amp Activated Protein Kinase

scholarly journals Protein kinase A activates protein phosphatase 2A by phosphorylation of the B56  subunit

2007 ◽  
Vol 104 (8) ◽  
pp. 2979-2984 ◽  
Author(s):  
J.-H. Ahn ◽  
T. McAvoy ◽  
S. V. Rakhilin ◽  
A. Nishi ◽  
P. Greengard ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Phosphatase 2A ◽  
Kinase A

scholarly journals The Serine/Threonine Protein Phosphatase 2A (PP2A) Regulates Syk Activity in Human Platelets

2020 ◽  
Vol 21 (23) ◽  
pp. 8939
Author(s):  
Stephanie Makhoul ◽  
Elena Kumm ◽  
Pengyu Zhang ◽  
Ulrich Walter ◽  
Kerstin Jurk
Keyword(s):  
Protein Kinase ◽  
Platelet Activation ◽  
Protein Phosphatase ◽  
Feedback Inhibition ◽  
Protein Phosphatase 2A ◽  
Human Platelets ◽  
Membrane Receptors ◽  
Functional Link ◽  
S Protein ◽  
Phosphatase 2A

Distinct membrane receptors activate platelets by Src-family-kinase (SFK)-, immunoreceptor-tyrosine-based-activation-motif (ITAM)-dependent stimulation of spleen tyrosine kinase (Syk). Recently, we reported that platelet activation via glycoprotein (GP) VI or GPIbα stimulated the well-established Syk tyrosine (Y)-phosphorylation, but also stoichiometric, transient protein kinase C (PKC)-mediated Syk serine(S)297 phosphorylation in the regulatory interdomain-B, suggesting possible feedback inhibition. The transient nature of Syk S297 phosphorylation indicated the presence of an unknown Syk pS297 protein phosphatase. In this study, we hypothesize that the S-protein phosphatase 2A (PP2A) is responsible for Syk pS297 dephosphorylation, thereby affecting Syk Y-phosphorylation and activity in human washed platelets. Using immunoblotting, we show that specific inhibition of PP2A by okadaic acid (OA) alone leads to stoichiometric Syk S297 phosphorylation, as analyzed by Zn2+-Phos-tag gels, without affecting Syk Y-phosphorylation. Pharmacological inhibition of Syk by PRT060318 or PKC by GF109203X only minimally reduced OA-induced Syk S297 phosphorylation. PP2A inhibition by OA preceding GPVI-mediated platelet activation induced by convulxin extended Syk S297 phosphorylation but inhibited Syk Y-phosphorylation. Our data demonstrate a novel biochemical and functional link between the S-protein phosphatase PP2A and the Y-protein kinase Syk in human platelets, and suggest that PP2A represents a potential enhancer of GPVI-mediated Syk activity caused by Syk pS297 dephosphorylation.

scholarly journals Dissecting the Role of 5′-AMP for Allosteric Stimulation, Activation, and Deactivation of AMP-activated Protein Kinase

2006 ◽  
Vol 281 (43) ◽  
pp. 32207-32216 ◽  
Author(s):  
Marianne Suter ◽  
Uwe Riek ◽  
Roland Tuerk ◽  
Uwe Schlattner ◽  
Theo Wallimann ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Phosphatase ◽  
Energy Homeostasis ◽  
Adenine Nucleotides ◽  
Enzyme Preparations ◽  
Activity Measurements ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) is a heterotrimeric protein kinase that is crucial for cellular energy homeostasis of eukaryotic cells and organisms. Here we report on the activation of AMPK α1β1γ1 and α2β2γ1 by their upstream kinases (Ca2+/calmodulin-dependent protein kinase kinase-β and LKB1-MO25α-STRADα), the deactivation by protein phosphatase 2Cα, and on the extent of stimulation of AMPK by its allosteric activator AMP, using purified recombinant enzyme preparations. An accurate high pressure liquid chromatography-based method for AMPK activity measurements was established, which allowed for direct quantitation of the unphosphorylated and phosphorylated artificial peptide substrate, as well as the adenine nucleotides. Our results show a 1000-fold activation of AMPK by the combined effects of upstream kinase and saturating concentrations of AMP. The two AMPK isoforms exhibit similar specific activities (6 μmol/min/mg) and do not differ significantly by their responsiveness to AMP. Due to the inherent instability of ATP and ADP, it proved impossible to assay AMPK activity in the absolute absence of AMP. However, the half-maximal stimulatory effect of AMP is reached below 2 μm. AMP does not appear to augment phosphorylation by upstream kinases in the purified in vitro system, but deactivation by dephosphorylation of AMPK α-subunits at Thr-172 by protein phosphatase 2Cα is attenuated by AMP. Furthermore, it is shown that neither purified NAD+ nor NADH alters the activity of AMPK in a concentration range of 0–300 μm, respectively. Finally, evidence is provided that ZMP, a compound formed in 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside-treated cells to activate AMPK in vivo, allosterically activates purified AMPK in vitro, but compared with AMP, maximal activity is not reached. These data shed new light on physiologically important aspects of AMPK regulation.

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