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Phosphorylated Peptide Derived from the Myosin Phosphatase Target Subunit Is a Novel Inhibitor of Protein Phosphatase-1. Int J Mol Sci 2023; 24:ijms24054789. [PMID: 36902219 PMCID: PMC10003451 DOI: 10.3390/ijms24054789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/20/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Identification of specific protein phosphatase-1 (PP1) inhibitors is of special importance regarding the study of its cellular functions and may have therapeutic values in diseases coupled to signaling processes. In this study, we prove that a phosphorylated peptide of the inhibitory region of myosin phosphatase (MP) target subunit (MYPT1), R690QSRRS(pT696)QGVTL701 (P-Thr696-MYPT1690-701), interacts with and inhibits the PP1 catalytic subunit (PP1c, IC50 = 3.84 µM) and the MP holoenzyme (Flag-MYPT1-PP1c, IC50 = 3.84 µM). Saturation transfer difference NMR measurements established binding of hydrophobic and basic regions of P-Thr696-MYPT1690-701 to PP1c, suggesting interactions with the hydrophobic and acidic substrate binding grooves. P-Thr696-MYPT1690-701 was dephosphorylated by PP1c slowly (t1/2 = 81.6-87.9 min), which was further impeded (t1/2 = 103 min) in the presence of the phosphorylated 20 kDa myosin light chain (P-MLC20). In contrast, P-Thr696-MYPT1690-701 (10-500 µM) slowed down the dephosphorylation of P-MLC20 (t1/2 = 1.69 min) significantly (t1/2 = 2.49-10.06 min). These data are compatible with an unfair competition mechanism between the inhibitory phosphopeptide and the phosphosubstrate. Docking simulations of the PP1c-P-MYPT1690-701 complexes with phosphothreonine (PP1c-P-Thr696-MYPT1690-701) or phosphoserine (PP1c-P-Ser696-MYPT1690-701) suggested their distinct poses on the surface of PP1c. In addition, the arrangements and distances of the surrounding coordinating residues of PP1c around the phosphothreonine or phosphoserine at the active site were distinct, which may account for their different hydrolysis rate. It is presumed that P-Thr696-MYPT1690-701 binds tightly at the active center but the phosphoester hydrolysis is less preferable compared to P-Ser696-MYPT1690-701 or phosphoserine substrates. Moreover, the inhibitory phosphopeptide may serve as a template to synthesize cell permeable PP1-specific peptide inhibitors.
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Eto M, Katsuki S, Ohashi M, Miyagawa Y, Tanaka Y, Takeya K, Kitazawa T. Possible roles of N- and C-terminal unstructured tails of CPI-17 in regulating Ca<sup>2+</sup> sensitization force of smooth muscle. J Smooth Muscle Res 2022; 58:22-33. [PMID: 35418530 PMCID: PMC9006046 DOI: 10.1540/jsmr.58.22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
CPI-17 regulates the myosin phosphatase and mediates the agonist-induced contraction of
smooth muscle. PKC and ROCK phosphorylate CPI-17 at Thr38 leading to a conformational
change of the central inhibitory domain (PHIN domain). The N- and C-terminal tails of
CPI-17 are predicted as unstructured loops and their sequences are conserved among
mammals. Here we characterized CPI-17 N- and C-terminal unstructured tails using
recombinant proteins that lack the potions. Recombinant CPI-17 proteins at a physiologic
level (10 µM) were doped into beta-escin-permeabilized smooth muscle strips for
Ca2+ sensitization force measurement. The ectopic full-length CPI-17
augmented the PDBu-induced Ca2+ sensitization force at pCa6.3, indicating
myosin phosphatase inhibition. Deletion of N- and C-terminal tails of CPI-17 attenuated
the extent of PDBu-induced Ca2+-sensitization force. The N-terminal deletion
dampened phosphorylation at Thr38 by protein kinase C (PKC), and the C-terminal truncation
lowered the affinity to the myosin phosphatase. Under the physiologic conditions, PKC and
myosin phosphatase may recognize CPI-17 N-/C-terminal unstructured tails inducing
Ca2+ sensitization force in smooth muscle cells.
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Affiliation(s)
- Masumi Eto
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoino-oka, Imabari, Ehime 794-8555, Japan
| | - Shuichi Katsuki
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoino-oka, Imabari, Ehime 794-8555, Japan
| | - Minami Ohashi
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoino-oka, Imabari, Ehime 794-8555, Japan
| | - Yui Miyagawa
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoino-oka, Imabari, Ehime 794-8555, Japan
| | - Yoshinori Tanaka
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoino-oka, Imabari, Ehime 794-8555, Japan
| | - Kosuke Takeya
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoino-oka, Imabari, Ehime 794-8555, Japan
| | - Toshio Kitazawa
- Department of Mol Physiol & Biophysics, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Targeting protein phosphatase PP2A for cancer therapy: development of allosteric pharmaceutical agents. Clin Sci (Lond) 2021; 135:1545-1556. [PMID: 34192314 DOI: 10.1042/cs20201367] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/15/2021] [Accepted: 07/16/2021] [Indexed: 01/26/2023]
Abstract
Tumor initiation is driven by oncogenes that activate signaling networks for cell proliferation and survival involving protein phosphorylation. Protein kinases in these pathways have proven to be effective targets for pharmaceutical inhibitors that have progressed to the clinic to treat various cancers. Here, we offer a narrative about the development of small molecule modulators of the protein Ser/Thr phosphatase 2A (PP2A) to reduce the activation of cell proliferation and survival pathways. These novel drugs promote the assembly of select heterotrimeric forms of PP2A that act to limit cell proliferation. We discuss the potential for the near-term translation of this approach to the clinic for cancer and other human diseases.
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Kamenz J, Gelens L, Ferrell JE. Bistable, Biphasic Regulation of PP2A-B55 Accounts for the Dynamics of Mitotic Substrate Phosphorylation. Curr Biol 2020; 31:794-808.e6. [PMID: 33357450 PMCID: PMC7904671 DOI: 10.1016/j.cub.2020.11.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/20/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022]
Abstract
The phosphorylation of mitotic proteins is bistable, which contributes to the decisiveness of the transitions into and out of M phase. The bistability in substrate phosphorylation has been attributed to bistability in the activation of the cyclin-dependent kinase Cdk1. However, more recently it has been suggested that bistability also arises from positive feedback in the regulation of the Cdk1-counteracting phosphatase PP2A-B55. Here, we demonstrate biochemically using Xenopus laevis egg extracts that the Cdk1-counter-acting phosphatase PP2A-B55 functions as a bistable switch, even when the bistability of Cdk1 activation is suppressed. In addition, Cdk1 regulates PP2A-B55 in a biphasic manner; low concentrations of Cdk1 activate PP2A-B55 and high concentrations inactivate it. As a consequence of this incoherent feedforward regulation, PP2A-B55 activity rises concurrently with Cdk1 activity during interphase and suppresses substrate phosphorylation. PP2A-B55 activity is then sharply downregulated at the onset of mitosis. During mitotic exit, Cdk1 activity initially falls with no obvious change in substrate phosphorylation; dephosphorylation then commences once PP2A-B55 spikes in activity. These findings suggest that changes in Cdk1 activity are permissive for mitotic entry and exit but that the changes in PP2A-B55 activity are the ultimate trigger. Mitotic transitions are accompanied by drastic changes in the phosphorylation state of proteins. Kamenz et al. demonstrate biochemically that the major mitotic phosphatase PP2A-B55 is regulated by incoherent feedforward and double-negative feedback loops to promote rapid and switch-like mitotic entry and exit.
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Affiliation(s)
- Julia Kamenz
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA.
| | - Lendert Gelens
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA; Laboratory of Dynamics in Biological Systems, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - James E Ferrell
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307, USA.
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Lang I, Virk G, Zheng DC, Young J, Nguyen MJ, Amiri R, Fong M, Arata A, Chadaideh KS, Walsh S, Weiser DC. The Evolution of Duplicated Genes of the Cpi-17/Phi-1 ( ppp1r14) Family of Protein Phosphatase 1 Inhibitors in Teleosts. Int J Mol Sci 2020; 21:ijms21165709. [PMID: 32784920 PMCID: PMC7460850 DOI: 10.3390/ijms21165709] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 08/07/2020] [Indexed: 11/29/2022] Open
Abstract
The Cpi-17 (ppp1r14) gene family is an evolutionarily conserved, vertebrate specific group of protein phosphatase 1 (PP1) inhibitors. When phosphorylated, Cpi-17 is a potent inhibitor of myosin phosphatase (MP), a holoenzyme complex of the regulatory subunit Mypt1 and the catalytic subunit PP1. Myosin phosphatase dephosphorylates the regulatory myosin light chain (Mlc2) and promotes actomyosin relaxation, which in turn, regulates numerous cellular processes including smooth muscle contraction, cytokinesis, cell motility, and tumor cell invasion. We analyzed zebrafish homologs of the Cpi-17 family, to better understand the mechanisms of myosin phosphatase regulation. We found single homologs of both Kepi (ppp1r14c) and Gbpi (ppp1r14d) in silico, but we detected no expression of these genes during early embryonic development. Cpi-17 (ppp1r14a) and Phi-1 (ppp1r14b) each had two duplicate paralogs, (ppp1r14aa and ppp1r14ab) and (ppp1r14ba and ppp1r14bb), which were each expressed during early development. The spatial expression pattern of these genes has diverged, with ppp1r14aa and ppp1r14bb expressed primarily in smooth muscle and skeletal muscle, respectively, while ppp1r14ab and ppp1r14ba are primarily expressed in neural tissue. We observed that, in in vitro and heterologous cellular systems, the Cpi-17 paralogs both acted as potent myosin phosphatase inhibitors, and were indistinguishable from one another. In contrast, the two Phi-1 paralogs displayed weak myosin phosphatase inhibitory activity in vitro, and did not alter myosin phosphorylation in cells. Through deletion and chimeric analysis, we identified that the difference in specificity for myosin phosphatase between Cpi-17 and Phi-1 was encoded by the highly conserved PHIN (phosphatase holoenzyme inhibitory) domain, and not the more divergent N- and C- termini. We also showed that either Cpi-17 paralog can rescue the knockdown phenotype, but neither Phi-1 paralog could do so. Thus, we provide new evidence about the biochemical and developmental distinctions of the zebrafish Cpi-17 protein family.
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Affiliation(s)
- Irene Lang
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Guneet Virk
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Dale C. Zheng
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Jason Young
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Michael J. Nguyen
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Rojin Amiri
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Michelle Fong
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Alisa Arata
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
| | - Katia S. Chadaideh
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Susan Walsh
- Life Sciences, Soka University of America, Aliso Viejo, CA 92656, USA;
| | - Douglas C. Weiser
- Department of Biological Sciences, University of the Pacific, Stockton, CA 98211, USA; (I.L.); (G.V.); (D.C.Z.); (J.Y.); (M.J.N.); (R.A.); (M.F.); (A.A.); (K.S.C.)
- Correspondence: ; Tel.: +1-209-946-2955
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Brayden D, Hill T, Fairlie D, Maher S, Mrsny R. Systemic delivery of peptides by the oral route: Formulation and medicinal chemistry approaches. Adv Drug Deliv Rev 2020; 157:2-36. [PMID: 32479930 DOI: 10.1016/j.addr.2020.05.007] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 02/07/2023]
Abstract
In its 33 years, ADDR has published regularly on the po5tential of oral delivery of biologics especially peptides and proteins. In the intervening period, analysis of the preclinical and clinical trial failures of many purported platform technologies has led to reflection on the true status of the field and reigning in of expectations. Oral formulations of semaglutide, octreotide, and salmon calcitonin have completed Phase III trials, with oral semaglutide being approved by the FDA in 2019. The progress made with oral peptide formulations based on traditional permeation enhancers is against a background of low and variable oral bioavailability values of ~1%, leading to a current perception that only potent peptides with a viable cost of synthesis can be realistically considered. Desirable features of candidates should include a large therapeutic index, some stability in the GI tract, a long elimination half-life, and a relatively low clearance rate. Administration in nanoparticle formats have largely disappointed, with few prototypes reaching clinical trials: insufficient particle loading, lack of controlled release, low epithelial particle uptake, and lack of scalable synthesis being the main reasons for discontinuation. Disruptive technologies based on engineered devices promise improvements, but scale-up and toxicology aspects are issues to address. In parallel, medicinal chemists are synthesizing stable hydrophobic macrocyclic candidate peptides of lower molecular weight and with potential for greater oral bioavailability than linear peptides, but perhaps without the same requirement for elaborate drug delivery systems. In summary, while there have been advances in understanding the limitations of peptides for oral delivery, low membrane permeability, metabolism, and high clearance rates continue to hamper progress.
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Brautigan DL, Shenolikar S. Protein Serine/Threonine Phosphatases: Keys to Unlocking Regulators and Substrates. Annu Rev Biochem 2019; 87:921-964. [PMID: 29925267 DOI: 10.1146/annurev-biochem-062917-012332] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein serine/threonine phosphatases (PPPs) are ancient enzymes, with distinct types conserved across eukaryotic evolution. PPPs are segregated into types primarily on the basis of the unique interactions of PPP catalytic subunits with regulatory proteins. The resulting holoenzymes dock substrates distal to the active site to enhance specificity. This review focuses on the subunit and substrate interactions for PPP that depend on short linear motifs. Insights about these motifs from structures of holoenzymes open new opportunities for computational biology approaches to elucidate PPP networks. There is an expanding knowledge base of posttranslational modifications of PPP catalytic and regulatory subunits, as well as of their substrates, including phosphorylation, acetylation, and ubiquitination. Cross talk between these posttranslational modifications creates PPP-based signaling. Knowledge of PPP complexes, signaling clusters, as well as how PPPs communicate with each other in response to cellular signals should unlock the doors to PPP networks and signaling "clouds" that orchestrate and coordinate different aspects of cell physiology.
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Affiliation(s)
- David L Brautigan
- Center for Cell Signaling and Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA;
| | - Shirish Shenolikar
- Signature Research Programs in Cardiovascular and Metabolic Disorders and Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore 169857
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Nilsson J. Protein phosphatases in the regulation of mitosis. J Cell Biol 2018; 218:395-409. [PMID: 30446607 PMCID: PMC6363451 DOI: 10.1083/jcb.201809138] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/29/2018] [Accepted: 10/29/2018] [Indexed: 12/15/2022] Open
Abstract
The accurate segregation of genetic material to daughter cells during mitosis depends on the precise coordination and regulation of hundreds of proteins by dynamic phosphorylation. Mitotic kinases are major regulators of protein function, but equally important are protein phosphatases that balance their actions, their coordinated activity being essential for accurate chromosome segregation. Phosphoprotein phosphatases (PPPs) that dephosphorylate phosphoserine and phosphothreonine residues are increasingly understood as essential regulators of mitosis. In contrast to kinases, the lack of a pronounced peptide-binding cleft on the catalytic subunit of PPPs suggests that these enzymes are unlikely to be specific. However, recent exciting insights into how mitotic PPPs recognize specific substrates have revealed that they are as specific as kinases. Furthermore, the activities of PPPs are tightly controlled at many levels to ensure that they are active only at the proper time and place. Here, I will discuss substrate selection and regulation of mitotic PPPs focusing mainly on animal cells and explore how these actions control mitosis, as well as important unanswered questions.
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Affiliation(s)
- Jakob Nilsson
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
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Kiss A, Erdődi F, Lontay B. Myosin phosphatase: Unexpected functions of a long-known enzyme. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:2-15. [PMID: 30076859 DOI: 10.1016/j.bbamcr.2018.07.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 07/09/2018] [Accepted: 07/26/2018] [Indexed: 01/08/2023]
Abstract
Myosin phosphatase (MP) holoenzyme is a Ser/Thr specific enzyme, which is the member of protein phosphatase type 1 (PP1) family and composed of a PP1 catalytic subunit (PP1c/PPP1CB) and a myosin phosphatase targeting subunit (MYPT1/PPP1R12A). PP1c is required for the catalytic activity of the holoenzyme, while MYPT1 regulates MP through targeting the holoenzyme to its substrates. Above the well-characterized function of MP, as the major regulator of smooth muscle contractility mediating the dephosphorylation of 20 kDa myosin light chain, accumulating data support its role in other, non-contractile functions. In this review, we summarize the scaffold function of MP holoenzyme and its roles in processes such as cell cycle, development, gene expression regulation and neurotransmitter release. In particular, we highlight novel interacting proteins of MYPT1 and pathophysiological functions of MP relevant to tumorigenesis, insulin resistance and neurodegenerative disorders. This article is part of a Special Issue entitled: Protein Phosphatases as Critical Regulators for Cellular Homeostasis edited by Prof. Peter Ruvolo and Dr. Veerle Janssens.
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Affiliation(s)
- Andrea Kiss
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Ferenc Erdődi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Beáta Lontay
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
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Wang F, Sun Y. Overexpression of Myosin Phosphatase Target Subunit 1 (MYPT1) Inhibits Tumor Progression and Metastasis of Gastric Cancer. Med Sci Monit 2018; 24:2508-2517. [PMID: 29687789 PMCID: PMC5937360 DOI: 10.12659/msm.906852] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background Myosin phosphatase target subunit 1 (MYPT1) serves as a subgroup of myosin phosphatases, and is frequently low-expressed in human cancers. However, little is known about the effects of MYPT1 in gastric cancer (GC). Material/Methods In our study, MYPT1 expression was detected by quantitative real-time reverse transcription PCR (qRT-PCR) in GC tissues, different advanced pathological stages of GC tissues, and preoperative and postoperative patients. Kaplan-Meier analysis was used to measure the overall survival of GC patients. MYPT1 expression was analyzed by qRT-PCR and Western blot assays in GES-1 cells and GC cells. Cell proliferation, cycle, and migration and invasion abilities were detected by CCK-8, flow cytometry, and Transwell assays. E-cadherin, TIMP-2, MMP-2, MMP-9 RhoA, and p-RhoA expressions were assessed by qRT-PCR and Western blot assays in treated SNU-5 cells. Results Our results indicated that MYPT1 was down-regulated in GC tissues and cells, and is related to clinical stages and overall survival of GC. Functional research demonstrated that overexpression of MYPT1 can inhibit cell proliferation, cell cycle progression, and migration and invasion of GC cells. Many studies on mechanisms reported that overexpression of MYPT1 dramatically improved the expression levels of cell cycle-related genes (Cyclin D1 and c-myc), significantly increased epithelial marker (E-cadherin) expression, and decreased invasion-associated genes (TIMP-2 and MMP-2) expressions in SNU-5 cells. In addition, we found that MYPT1 suppressed RhoA phosphorylation. Conclusions We verified that MYPT1 inhibits GC cell proliferation and metastasis by regulating RhoA phosphorylation.
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Affiliation(s)
- Fengyong Wang
- Department of Gastrointestinal and Pancreatic Surgery, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang, China (mainland)
| | - Yuanshui Sun
- Department of Gastrointestinal and Pancreatic Surgery, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang, China (mainland)
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