1
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Papi RM, Tasioulis KS, Kechagioglou PV, Papaioannou MA, Andriotis EG, Kyriakidis DA. Carbon Nanotube-Mediated Delivery of PTEN Variants: In Vitro Antitumor Activity in Breast Cancer Cells. Molecules 2024; 29:2785. [PMID: 38930850 PMCID: PMC11206347 DOI: 10.3390/molecules29122785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/27/2024] [Accepted: 06/08/2024] [Indexed: 06/28/2024] Open
Abstract
Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a crucial tumor suppressor protein with frequent mutations and alterations. Although protein therapeutics are already integral to numerous medical fields, their potential remains nascent. This study aimed to investigate the impact of stable, unphosphorylated recombinant human full-length PTEN and its truncated variants, regarding their tumor suppression activity with multiwalled-carbon nanotubes (MW-CNTs) as vehicles for their delivery in breast cancer cells (T-47D, ZR-75-1, and MCF-7). The cloning, overexpression, and purification of PTEN variants were achieved from E. coli, followed by successful binding to CNTs. Cell incubation with protein-functionalized CNTs revealed that the full-length PTEN-CNTs significantly inhibited cancer cell growth and stimulated apoptosis in ZR-75-1 and MCF-7 cells, while truncated PTEN fragments on CNTs had a lesser effect. The N-terminal fragment, despite possessing the active site, did not have the same effect as the full length PTEN, emphasizing the necessity of interaction with the C2 domain in the C-terminal tail. Our findings highlight the efficacy of full-length PTEN in inhibiting cancer growth and inducing apoptosis through the alteration of the expression levels of key apoptotic markers. In addition, the utilization of carbon nanotubes as a potent PTEN protein delivery system provides valuable insights for future applications in in vivo models and clinical studies.
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Affiliation(s)
- Rigini M. Papi
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece; (K.S.T.); (P.V.K.); (D.A.K.)
| | - Konstantinos S. Tasioulis
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece; (K.S.T.); (P.V.K.); (D.A.K.)
| | - Petros V. Kechagioglou
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece; (K.S.T.); (P.V.K.); (D.A.K.)
| | - Maria A. Papaioannou
- Laboratory of Biological Chemistry, School of Medicine, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
| | - Eleftherios G. Andriotis
- Laboratory of Organic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
| | - Dimitrios A. Kyriakidis
- Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece; (K.S.T.); (P.V.K.); (D.A.K.)
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2
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Gulia S, Chandra P, Das A. The Prognosis of Cancer Depends on the Interplay of Autophagy, Apoptosis, and Anoikis within the Tumor Microenvironment. Cell Biochem Biophys 2023; 81:621-658. [PMID: 37787970 DOI: 10.1007/s12013-023-01179-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2023] [Indexed: 10/04/2023]
Abstract
Within the tumor microenvironment, the fight between the immune system and cancer influences tumor transformation. Metastasis formation is an important stage in the progression of cancer. This process is aided by cellular detachment and resistance to anoikis, which are achieved by altering intercellular signaling. Autophagy, specifically pro-survival autophagy, aids cancer cells in developing treatment resistance. Numerous studies have shown that autophagy promotes tumor growth and resistance to anoikis. To regulate protective autophagy, cancer-related genes phosphorylate both pro- and anti-apoptotic proteins. Apoptosis, a type of controlled cell death, eliminates damaged or unwanted cells. Anoikis is a type of programmed cell death in which cells lose contact with the extracellular matrix. The dysregulation of these cellular pathways promotes tumor growth and spread. Apoptosis, anoikis, and autophagy interact meticulously and differently depending on the cellular circumstances. For instance, autophagy can protect cancer cells from apoptosis by removing cellular components that are damaged and might otherwise trigger apoptotic pathways. Similarly, anoikis dysregulation can trigger autophagy by causing cellular harm and metabolic stress. In order to prevent or treat metastatic disease, specifically, targeting these cellular mechanisms may present a promising prospect for cancer therapy. This review discourses the state of our understanding of the molecular and cellular mechanisms underlying tumor transformation and the establishment of metastatic tumors. To enhance the prognosis for cancer, we highlight and discuss potential therapeutic approaches that target these processes and genes involved in them.
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Affiliation(s)
- Shweta Gulia
- Department of Biotechnology, Delhi Technological University, Main Bawana Road, Delhi, 110042, India
| | - Prakash Chandra
- Department of Biotechnology, Delhi Technological University, Main Bawana Road, Delhi, 110042, India
| | - Asmita Das
- Department of Biotechnology, Delhi Technological University, Main Bawana Road, Delhi, 110042, India.
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3
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Li D, Yang Y, Lv C, Wang Y, Chao X, Huang J, Singh SP, Yuan Y, Zhang C, Lou J, Gao P, Huang S, Li B, Cai H. GxcM-Fbp17/RacC-WASP signaling regulates polarized cortex assembly in migrating cells via Arp2/3. J Cell Biol 2023; 222:e202208151. [PMID: 37010470 PMCID: PMC10072221 DOI: 10.1083/jcb.202208151] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 02/02/2023] [Accepted: 03/17/2023] [Indexed: 04/04/2023] Open
Abstract
The actin-rich cortex plays a fundamental role in many cellular processes. Its architecture and molecular composition vary across cell types and physiological states. The full complement of actin assembly factors driving cortex formation and how their activities are spatiotemporally regulated remain to be fully elucidated. Using Dictyostelium as a model for polarized and rapidly migrating cells, we show that GxcM, a RhoGEF localized specifically in the rear of migrating cells, functions together with F-BAR protein Fbp17, a small GTPase RacC, and the actin nucleation-promoting factor WASP to coordinately promote Arp2/3 complex-mediated cortical actin assembly. Overactivation of this signaling cascade leads to excessive actin polymerization in the rear cortex, whereas its disruption causes defects in cortical integrity and function. Therefore, apart from its well-defined role in the formation of the protrusions at the cell front, the Arp2/3 complex-based actin carries out a previously unappreciated function in building the rear cortical subcompartment in rapidly migrating cells.
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Affiliation(s)
- Dong Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yihong Yang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Chenglin Lv
- Department of Engineering Mechanics, Applied Mechanics Laboratory, Institute of Biomechanics and Medical Engineering, Tsinghua University, Beijing, China
| | - Yingjie Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaoting Chao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jiafeng Huang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | | | - Ye Yuan
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Chengyu Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jizhong Lou
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Pu Gao
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bo Li
- Department of Engineering Mechanics, Applied Mechanics Laboratory, Institute of Biomechanics and Medical Engineering, Tsinghua University, Beijing, China
| | - Huaqing Cai
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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4
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Langdon CG. Nuclear PTEN's Functions in Suppressing Tumorigenesis: Implications for Rare Cancers. Biomolecules 2023; 13:biom13020259. [PMID: 36830628 PMCID: PMC9953540 DOI: 10.3390/biom13020259] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/25/2023] [Accepted: 01/28/2023] [Indexed: 01/31/2023] Open
Abstract
Phosphatase and tensin homolog (PTEN) encodes a tumor-suppressive phosphatase with both lipid and protein phosphatase activity. The tumor-suppressive functions of PTEN are lost through a variety of mechanisms across a wide spectrum of human malignancies, including several rare cancers that affect pediatric and adult populations. Originally discovered and characterized as a negative regulator of the cytoplasmic, pro-oncogenic phosphoinositide-3-kinase (PI3K) pathway, PTEN is also localized to the nucleus where it can exert tumor-suppressive functions in a PI3K pathway-independent manner. Cancers can usurp the tumor-suppressive functions of PTEN to promote oncogenesis by disrupting homeostatic subcellular PTEN localization. The objective of this review is to describe the changes seen in PTEN subcellular localization during tumorigenesis, how PTEN enters the nucleus, and the spectrum of impacts and consequences arising from disrupted PTEN nuclear localization on tumor promotion. This review will highlight the immediate need in understanding not only the cytoplasmic but also the nuclear functions of PTEN to gain more complete insights into how important PTEN is in preventing human cancers.
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Affiliation(s)
- Casey G. Langdon
- Department of Pediatrics, Darby Children’s Research Institute, Medical University of South Carolina, Charleston, SC 29425, USA; ; Tel.: +1-(843)-792-9289
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
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5
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Kotzampasi DM, Premeti K, Papafotika A, Syropoulou V, Christoforidis S, Cournia Z, Leondaritis G. The orchestrated signaling by PI3Kα and PTEN at the membrane interface. Comput Struct Biotechnol J 2022; 20:5607-5621. [PMID: 36284707 PMCID: PMC9578963 DOI: 10.1016/j.csbj.2022.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 11/16/2022] Open
Abstract
The oncogene PI3Kα and the tumor suppressor PTEN represent two antagonistic enzymatic activities that regulate the interconversion of the phosphoinositide lipids PI(4,5)P2 and PI(3,4,5)P3 in membranes. As such, they are defining components of phosphoinositide-based cellular signaling and membrane trafficking pathways that regulate cell survival, growth, and proliferation, and are often deregulated in cancer. In this review, we highlight aspects of PI3Kα and PTEN interplay at the intersection of signaling and membrane trafficking. We also discuss the mechanisms of PI3Kα- and PTEN- membrane interaction and catalytic activation, which are fundamental for our understanding of the structural and allosteric implications on signaling at the membrane interface and may aid current efforts in pharmacological targeting of these proteins.
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Affiliation(s)
- Danai Maria Kotzampasi
- Biomedical Research Foundation, Academy of Athens, Athens 11527, Greece
- Department of Biology, University of Crete, Heraklion 71500, Greece
| | - Kyriaki Premeti
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
| | - Alexandra Papafotika
- Laboratory of Biological Chemistry, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina 45110, Greece
- Biomedical Research Institute, Foundation for Research and Technology, Ioannina 45110, Greece
| | - Vasiliki Syropoulou
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
| | - Savvas Christoforidis
- Laboratory of Biological Chemistry, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina 45110, Greece
- Biomedical Research Institute, Foundation for Research and Technology, Ioannina 45110, Greece
| | - Zoe Cournia
- Biomedical Research Foundation, Academy of Athens, Athens 11527, Greece
| | - George Leondaritis
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
- Institute of Biosciences, University Research Center of Ioannina, Ioannina 45110, Greece
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6
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Smith IN, Dawson JE, Krieger J, Thacker S, Bahar I, Eng C. Structural and Dynamic Effects of PTEN C-Terminal Tail Phosphorylation. J Chem Inf Model 2022; 62:4175-4190. [PMID: 36001481 PMCID: PMC9472802 DOI: 10.1021/acs.jcim.2c00441] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Indexed: 11/28/2022]
Abstract
The phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor gene encodes a tightly regulated dual-specificity phosphatase that serves as the master regulator of PI3K/AKT/mTOR signaling. The carboxy-terminal tail (CTT) is key to regulation and harbors multiple phosphorylation sites (Ser/Thr residues 380-385). CTT phosphorylation suppresses the phosphatase activity by inducing a stable, closed conformation. However, little is known about the mechanisms of phosphorylation-induced CTT-deactivation dynamics. Using explicit solvent microsecond molecular dynamics simulations, we show that CTT phosphorylation leads to a partially collapsed conformation, which alters the secondary structure of PTEN and induces long-range conformational rearrangements that encompass the active site. The active site rearrangements prevent localization of PTEN to the membrane, precluding lipid phosphatase activity. Notably, we have identified phosphorylation-induced allosteric coupling between the interdomain region and a hydrophobic site neighboring the active site in the phosphatase domain. Collectively, the results provide a mechanistic understanding of CTT phosphorylation dynamics and reveal potential druggable allosteric sites in a previously believed clinically undruggable protein.
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Affiliation(s)
- Iris N. Smith
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
| | - Jennifer E. Dawson
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
| | - James Krieger
- Department
of Computational and Systems Biology, University
of Pittsburgh, 800 Murdoch Building, 3420 Forbes Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Stetson Thacker
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
- Cleveland
Clinic Lerner College of Medicine, Case
Western Reserve University, 9500 Euclid Avenue, Cleveland, Ohio 44195, United
States
| | - Ivet Bahar
- Department
of Computational and Systems Biology, University
of Pittsburgh, 800 Murdoch Building, 3420 Forbes Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Charis Eng
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
- Cleveland
Clinic Lerner College of Medicine, Case
Western Reserve University, 9500 Euclid Avenue, Cleveland, Ohio 44195, United
States
- Case
Comprehensive Cancer Center, Case Western
Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
- Taussig
Cancer Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, United States
- Department
of Genetics and Genome Sciences, Case Western
Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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7
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Fadil SA, Janetopoulos C. The Polarized Redistribution of the Contractile Vacuole to the Rear of the Cell is Critical for Streaming and is Regulated by PI(4,5)P2-Mediated Exocytosis. Front Cell Dev Biol 2022; 9:765316. [PMID: 35928786 PMCID: PMC9344532 DOI: 10.3389/fcell.2021.765316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/20/2021] [Indexed: 12/05/2022] Open
Abstract
Dictyostelium discoideum amoebae align in a head to tail manner during the process of streaming during fruiting body formation. The chemoattractant cAMP is the chemoattractant regulating cell migration during this process and is released from the rear of cells. The process by which this cAMP release occurs has eluded investigators for many decades, but new findings suggest that this release can occur through expulsion during contractile vacuole (CV) ejection. The CV is an organelle that performs several functions inside the cell including the regulation of osmolarity, and discharges its content via exocytosis. The CV localizes to the rear of the cell and appears to be part of the polarity network, with the localization under the influence of the plasma membrane (PM) lipids, including the phosphoinositides (PIs), among those is PI(4,5)P2, the most abundant PI on the PM. Research on D. discoideum and neutrophils have shown that PI(4,5)P2 is enriched at the rear of migrating cells. In several systems, it has been shown that the essential regulator of exocytosis is through the exocyst complex, mediated in part by PI(4,5)P2-binding. This review features the role of the CV complex in D. discoideum signaling with a focus on the role of PI(4,5)P2 in regulating CV exocytosis and localization. Many of the regulators of these processes are conserved during evolution, so the mechanisms controlling exocytosis and membrane trafficking in D. discoideum and mammalian cells will be discussed, highlighting their important functions in membrane trafficking and signaling in health and disease.
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Affiliation(s)
- Sana A. Fadil
- Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia, PA, United States
- Department of Natural product, Faculty of Pharmacy, King Abdulaziz University, Saudia Arabia
| | - Chris Janetopoulos
- Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia, PA, United States
- The Science Research Institute, Albright College, Reading, PA, United States
- The Department of Cell Biology at Johns Hopkins University School of Medicine, Baltimore, MD, United States
- *Correspondence: Chris Janetopoulos,
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8
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Al-Fahad D, Alyaseen F, Al-Amery A, Singh G, Srinath M, Rehman HM, Abbas Y. Kinetic Changes of Ptdins (3,4,5) P3 within Fast and Slow Turnover Rates of Focal Adhesion. Rep Biochem Mol Biol 2022; 11:262-269. [PMID: 36164635 PMCID: PMC9455192 DOI: 10.52547/rbmb.11.2.262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 01/02/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND The assembly and disassembly of the focal adhesions (FA) components occurs throughout life cycle of adhesion, with conservation of balance between removal and recruitment rate during temporal stages. Previous studies have demonstrated that phosphotidyilinositols play a role in regulating FA turnover. However, a little attention has been given to quantify the dynamics changes of Phosphatidylinositol 3,4,5-trisphosphate (PtdIns (3,4,5) P3) within and during fast and slow turnover rates of FA. METHODS In this study, we developed a protein purification MDA-MB-231 breast cancer cell line was used as a model in this study due to high metastatic and motile. These cells were co-transfected with GFP- paxillin/vinculin, as FA marker, and the GFP/mCherry-Btk-PH, as a biosensor to visualize PtdIns (3,4,5) P3. Confocal time-lapse images were used to monitor changes or differences in the local generation of PtdIns (3,4,5) P3 within and during assembly and disassembly of FA. Following transfection, immunostaining was used to examine the spatial co-localization between FA and PtdIns (3,4,5) P3. RESULTS Our data demonstrated that PtdIns (3,4,5) P3 co-localized with FAs and increase during assembly and decline during disassembly of FA which exhibits slow turnover rates and was in a constant level during assembly and disassembly of FA that displays fast turnover rates. DISCUSSION Our result suggested that the dynamic changes of PtdIns (3,4,5) P3, it may depend on components undergo turnover, such that early, nascent FA displays fast turnover rates and mature FA exhibits slow turnover rates. Thus, the local enrichment of PtdIns (3,4,5) P3 enhances FA assembly and disassembly activation.
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Affiliation(s)
- Dhurgham Al-Fahad
- Department of Pharmaceutical Sciences, College of Pharmacy University of Thi-Qar, Thi-Qar 64001, Iraq.
| | - Firas Alyaseen
- Department of Pharmaceutical Sciences, College of Pharmacy University of Thi-Qar, Thi-Qar 64001, Iraq.
| | - Ahmed Al-Amery
- Department of Physiology, College of Medicine, University of Thi-Qar, Iraq.
| | - Gagandeep Singh
- Viral Research and Diagnostic Laboratory, Department of Microbiology, Osmanian Medical College, Hyderabad, Telangana, India.
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India.
| | - Mote Srinath
- Viral Research and Diagnostic Laboratory, Department of Microbiology, Osmanian Medical College, Hyderabad, Telangana, India.
| | | | - Yahya Abbas
- Department of Biology, College of Science, University of Thi-Qar, Thi-Qar, 64001 Iraq.
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9
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Mizutani N, Kawanabe A, Jinno Y, Narita H, Yonezawa T, Nakagawa A, Okamura Y. Interaction between S4 and the phosphatase domain mediates electrochemical coupling in voltage-sensing phosphatase (VSP). Proc Natl Acad Sci U S A 2022; 119:e2200364119. [PMID: 35733115 PMCID: PMC9245683 DOI: 10.1073/pnas.2200364119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/13/2022] [Indexed: 11/18/2022] Open
Abstract
Voltage-sensing phosphatase (VSP) consists of a voltage sensor domain (VSD) and a cytoplasmic catalytic region (CCR), which is similar to phosphatase and tensin homolog (PTEN). How the VSD regulates the innate enzyme component of VSP remains unclear. Here, we took a combined approach that entailed the use of electrophysiology, fluorometry, and structural modeling to study the electrochemical coupling in Ciona intestinalis VSP. We found that two hydrophobic residues at the lowest part of S4 play an essential role in the later transition of VSD-CCR coupling. Voltage clamp fluorometry and disulfide bond locking indicated that S4 and its neighboring linker move as one helix (S4-linker helix) and approach the hydrophobic spine in the CCR, a structure located near the cell membrane and also conserved in PTEN. We propose that the hydrophobic spine operates as a hub for translating an electrical signal into a chemical one in VSP.
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Affiliation(s)
- Natsuki Mizutani
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Akira Kawanabe
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yuka Jinno
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hirotaka Narita
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Tomoko Yonezawa
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Atsushi Nakagawa
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasushi Okamura
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
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10
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Kato T. Immunofluorescence Detection of Plasma Membranous PTEN in Cultured Cells. J Histochem Cytochem 2022; 70:289-297. [PMID: 35199573 PMCID: PMC8971685 DOI: 10.1369/00221554221082539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 02/04/2022] [Indexed: 11/22/2022] Open
Abstract
PTEN is a well-known tumor suppressor with various functions that depend on its intracellular localization. Green fluorescent protein (GFP)-tagged live-cell images clarified the crucial amino acids needed to regulate the localization of PTEN in cells. However, it currently remains unknown whether GFP itself affects the intracellular localization of PTEN and its mutants, and the establishment of fixed-cell imaging is important for identifying the exact location of PTEN in cells. I herein investigated a number of immunofluorescence strategies for cell fixation, membrane permeabilization, and antigen retrieval. Permeabilization by detergents was necessary to observe nuclear and cytosolic PTEN in paraformaldehyde (PFA)-fixed cells; however, this permeabilization was not always valid. On the other hand, antigen retrieval by the pre-boiled EDTA treatment was useful for detecting plasma membranous PTEN in PFA-fixed cells in the same manner as in in vivo studies. Furthermore, methanol-fixed images of PTEN were consistent with GFP-tagged live-cell images. Two immunofluorescence methods (the PFA-fixed/pre-boiled EDTA treatment and methanol fixation) are applicable to investigations of the intracellular localization of PTEN without a GFP tag in cultured cells. In conclusion, live-cell imaging and appropriate immunofluorescence including a novel antigen retrieval treatment were both useful for detecting the cellular localization of PTEN, particularly at the plasma membrane.
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Affiliation(s)
- Takashi Kato
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima, Japan
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11
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Li D, Sun F, Yang Y, Tu H, Cai H. Gradients of PI(4,5)P2 and PI(3,5)P2 Jointly Participate in Shaping the Back State of Dictyostelium Cells. Front Cell Dev Biol 2022; 10:835185. [PMID: 35186938 PMCID: PMC8855053 DOI: 10.3389/fcell.2022.835185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Polarity, which refers to the molecular or structural asymmetry in cells, is essential for diverse cellular functions. Dictyostelium has proven to be a valuable system for dissecting the molecular mechanisms of cell polarity. Previous studies in Dictyostelium have revealed a range of signaling and cytoskeletal proteins that function at the leading edge to promote pseudopod extension and migration. In contrast, how proteins are localized to the trailing edge is not well understood. By screening for asymmetrically localized proteins, we identified a novel trailing-edge protein we named Teep1. We show that a charged surface formed by two pleckstrin homology (PH) domains in Teep1 is necessary and sufficient for targeting it to the rear of cells. Combining biochemical and imaging analyses, we demonstrate that Teep1 interacts preferentially with PI(4,5)P2 and PI(3,5)P2in vitro and simultaneous elimination of these lipid species in cells blocks the membrane association of Teep1. Furthermore, a leading-edge localized myotubularin phosphatase likely mediates the removal of PI(3,5)P2 from the front, as well as the formation of a back-to-front gradient of PI(3,5)P2. Together our data indicate that PI(4,5)P2 and PI(3,5)P2 on the plasma membrane jointly participate in shaping the back state of Dictyostelium cells.
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Affiliation(s)
- Dong Li
- School of Life Sciences, University of Science and Technology of China, Hefei, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Feifei Sun
- School of Life Sciences, University of Science and Technology of China, Hefei, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yihong Yang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Hui Tu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Huaqing Cai
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Huaqing Cai,
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12
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Al-Fahad D, Al-Harbi B, Abbas Y, Al-Yaseen F. A Comparative Study to Visualize PtdIns(4,5) P2 and PtdIns(3,4,5) P3 in MDA-MB-231 Breast Cancer Cell Line. Rep Biochem Mol Biol 2022; 10:518-526. [PMID: 35291610 PMCID: PMC8903368 DOI: 10.52547/rbmb.10.4.518] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 09/19/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5) P3) and Phosphatidylinositol 4,5-trisphosphate (PtdIns(4,5) P2] form an insignificant amount of phospholipids but play important roles in controlling membrane-bound signalling. Little attention has been given to visualize and monitor changes or differences in the local generation of PtdIns(4,5) P2 and PtdIns(3,4,5) P3 in the cell membranes of MDA-MB-231 breast cancer cell lines. METHODS PLCδ1-PH-GFP and Btk-PH-GFP were used as biosensors to detected PtdIns(4,5) P2 and PtdIns(3,4,5)P3 respectively. These biosensors and antibodies were transfected, immuostained and then visualized by confocal microscopy on different cell surfaces. RESULTS Our results showed that PLCδ1-PH-GFP/mCherry was localized at the cell membrane, while Btk-PH-GFP/mCherry was sometimes localized at the cell membrane but there was also a large amount of fluorescence present in the cytosol and nucleus. Our results also showed that the cells that expressed low levels of Btk-PH-GFP the fluorescence was predominantly localised to the cell membrane. While the cells that expressed high levels of Btk-PH-GFP the fluorescence was localization in the cytosol and cell membrane. Our results demonstrated that both anti-PtdIns(4,5)P2 and anti-PtdIns(3,4,5)P3 antibodies were localized everywhere in cell. CONCLUSION Our results suggest that PLCδ1-PH-GFP and Btk-PH-GFP/mCherry have more specificity, reliability, suitability and accuracy than antibodies in binding with and detecting PtdIns(4,5)P2 and PtdIns(3,4,5)P3 and in studying the molecular dynamics of phospholipids in live and fixed cells.
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Affiliation(s)
- Dhurgham Al-Fahad
- Department of Pathological Analysis, College of Science, University of Thi-Qar, Thi-Qar 64001, Iraq.
| | - Bandar Al-Harbi
- Department of clinical laboratory, College of Applied Medical Science, University of Hail, Hail 81411, Saudia Arabia.
| | - Yahya Abbas
- Department of Biology, College of Science, University of Thi-Qar, Thi-Qar 64001, Iraq.
| | - Firas Al-Yaseen
- Department of Clinical Biochemistry, College of Pharmacy, University of Thi-Qar, Thi-Qar 64001, Iraq.
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13
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Senoo H, Murata D, Wai M, Arai K, Iwata W, Sesaki H, Iijima M. KARATE: PKA-induced KRAS4B-RHOA-mTORC2 supercomplex phosphorylates AKT in insulin signaling and glucose homeostasis. Mol Cell 2021; 81:4622-4634.e8. [PMID: 34551282 DOI: 10.1016/j.molcel.2021.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 06/06/2021] [Accepted: 08/30/2021] [Indexed: 01/22/2023]
Abstract
AKT is a serine/threonine kinase that plays an important role in metabolism, cell growth, and cytoskeletal dynamics. AKT is activated by two kinases, PDK1 and mTORC2. Although the regulation of PDK1 is well understood, the mechanism that controls mTORC2 is unknown. Here, by investigating insulin receptor signaling in human cells and biochemical reconstitution, we found that insulin induces the activation of mTORC2 toward AKT by assembling a supercomplex with KRAS4B and RHOA GTPases, termed KARATE (KRAS4B-RHOA-mTORC2 Ensemble). Insulin-induced KARATE assembly is controlled via phosphorylation of GTP-bound KRAS4B at S181 and GDP-bound RHOA at S188 by protein kinase A. By developing a KARATE inhibitor, we demonstrate that KRAS4B-RHOA interaction drives KARATE formation. In adipocytes, KARATE controls insulin-dependent translocation of the glucose transporter GLUT4 to the plasma membrane for glucose uptake. Thus, our work reveals a fundamental mechanism that activates mTORC2 toward AKT in insulin-regulated glucose homeostasis.
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Affiliation(s)
- Hiroshi Senoo
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daisuke Murata
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - May Wai
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kenta Arai
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wakiko Iwata
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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14
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Kato T, Igarashi A, Sesaki H, Iijima M. Generating a new mouse model for nuclear PTEN deficiency by a single K13R mutation. Genes Cells 2021; 26:1014-1022. [PMID: 34661323 DOI: 10.1111/gtc.12902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/12/2021] [Accepted: 10/14/2021] [Indexed: 12/01/2022]
Abstract
Many human diseases, including cancer and neurological abnormalities, are linked to deficiencies of phosphatase and tensin homolog deleted on chromosome ten (PTEN), a dual phosphatase that dephosphorylates both lipids and proteins. PTEN functions in multiple intracellular locations, including the plasma membrane and nucleus. Therefore, a critical challenge to understand the pathogenesis of PTEN-associated diseases is to determine the specific role of PTEN at different locations. Toward this goal, the current study generated a mouse line in which lysine 13, which is critical for the nuclear localization of PTEN, is changed to arginine in the lipid-binding domain using the CRISPR-Ca9 gene-editing system. We found that PTENK13R mice show a strong decrease in the localization of PTEN in the nucleus without affecting the protein stability, phosphatase activity, and phosphorylation in the C-terminal tail region. PTENK13R mice are viable but produce smaller neurons and develop microcephaly. These data demonstrate that PTENK13R mice provide a useful animal model to study the role of PTEN in the nucleus in vivo.
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Affiliation(s)
- Takashi Kato
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Faculty of Pharmacy, Yasuda Women's University, Hiroshima, Japan
| | - Atsushi Igarashi
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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15
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The structural basis of PTEN regulation by multi-site phosphorylation. Nat Struct Mol Biol 2021; 28:858-868. [PMID: 34625746 PMCID: PMC8549118 DOI: 10.1038/s41594-021-00668-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 08/26/2021] [Indexed: 12/12/2022]
Abstract
Phosphatase and tensin homolog (PTEN) is a phosphatidylinositol-3,4,5-triphosphate (PIP3) phospholipid phosphatase that is commonly mutated or silenced in cancer. PTEN's catalytic activity, cellular membrane localization and stability are orchestrated by a cluster of C-terminal phosphorylation (phospho-C-tail) events on Ser380, Thr382, Thr383 and Ser385, but the molecular details of this multi-faceted regulation have remained uncertain. Here we use a combination of protein semisynthesis, biochemical analysis, NMR, X-ray crystallography and computational simulations on human PTEN and its sea squirt homolog, VSP, to obtain a detailed picture of how the phospho-C-tail forms a belt around the C2 and phosphatase domains of PTEN. We also visualize a previously proposed dynamic N-terminal α-helix and show that it is key for PTEN catalysis but disordered upon phospho-C-tail interaction. This structural model provides a comprehensive framework for how C-tail phosphorylation can impact PTEN's cellular functions.
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16
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Song B, Gu Y, Jiang W, Li Y, Ayre WN, Liu Z, Yin T, Janetopoulos C, Iijima M, Devreotes P, Zhao M. Electric signals counterbalanced posterior vs anterior PTEN signaling in directed migration of Dictyostelium. Cell Biosci 2021; 11:111. [PMID: 34127068 PMCID: PMC8201722 DOI: 10.1186/s13578-021-00580-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 03/24/2021] [Indexed: 02/03/2023] Open
Abstract
Background Cells show directed migration response to electric signals, namely electrotaxis or galvanotaxis. PI3K and PTEN jointly play counterbalancing roles in this event via a bilateral regulation of PIP3 signaling. PI3K has been proved essential in anterior signaling of electrotaxing cells, whilst the role of PTEN remains elusive. Methods Dictyostelium cells with different genetic backgrounds were treated with direct current electric signals to investigate the genetic regulation of electrotaxis. Results We demonstrated that electric signals promoted PTEN phosphatase activity and asymmetrical translocation to the posterior plasma membrane of the electrotaxing cells. Electric stimulation produced a similar but delayed rear redistribution of myosin II, immediately before electrotaxis started. Actin polymerization is required for the asymmetric membrane translocation of PTEN and myosin. PTEN signaling is also responsible for the asymmetric anterior redistribution of PIP3/F-actin, and a biased redistribution of pseudopod protrusion in the forwarding direction of electrotaxing cells. Conclusions PTEN controls electrotaxis by coordinately regulating asymmetric redistribution of myosin to the posterior, and PIP3/F-actin to the anterior region of the directed migration cells. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-021-00580-x.
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Affiliation(s)
- Bing Song
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK. .,State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases, School of Stomatology, Fourth Military Medical University, Xi'an, China.
| | - Yu Gu
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK
| | - Wenkai Jiang
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK.,State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases, School of Stomatology, Fourth Military Medical University, Xi'an, China
| | - Ying Li
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK.,Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Biomedical Engineering, Tianjin, China
| | - Wayne Nishio Ayre
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK
| | - Zhipeng Liu
- Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Biomedical Engineering, Tianjin, China
| | - Tao Yin
- Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Biomedical Engineering, Tianjin, China
| | | | - Miho Iijima
- School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Peter Devreotes
- School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Min Zhao
- Department of Ophthalmology & Vision Science, UC Davis, School of Medicine, Davis, CA, 95618, USA. .,Department of Dermatology, UC Davis, School of Medicine, Davis, CA, 95618, USA.
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17
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Jang H, Smith IN, Eng C, Nussinov R. The mechanism of full activation of tumor suppressor PTEN at the phosphoinositide-enriched membrane. iScience 2021; 24:102438. [PMID: 34113810 PMCID: PMC8169795 DOI: 10.1016/j.isci.2021.102438] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/15/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022] Open
Abstract
Tumor suppressor PTEN, the second most highly mutated protein in cancer, dephosphorylates signaling lipid PIP3 produced by PI3Ks. Excess PIP3 promotes cell proliferation. The mechanism at the membrane of this pivotal phosphatase is unknown hindering drug discovery. Exploiting explicit solvent simulations, we tracked full-length PTEN trafficking from the cytosol to the membrane. We observed its interaction with membranes composed of zwitterionic phosphatidylcholine, anionic phosphatidylserine, and phosphoinositides, including signaling lipids PIP2 and PIP3. We tracked its moving away from the zwitterionic and getting absorbed onto anionic membrane that harbors PIP3. We followed it localizing on microdomains enriched in signaling lipids, as PI3K does, and observed PIP3 allosterically unfolding the N-terminal PIP2 binding domain, positioning it favorably for the polybasic motif interaction with PIP2. Finally, we determined PTEN catalytic action at the membrane, all in line with experimental observations, deciphering the mechanisms of how PTEN anchors to the membrane and restrains cancer. PTEN localizes on membrane microdomains enriched in phosphoinositides, as PI3K does Full PTEN activation requires both signaling lipids, PIP2 and PIP3 Strong salt bridge interactions sustain stable PTEN membrane localization Substrate-induced P loop conformational change implicates PTEN catalytic activity
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Affiliation(s)
- Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Iris Nira Smith
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Charis Eng
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA.,Center for Personalized Genetic Healthcare, Cleveland Clinic Community Care and Population Health, Cleveland, OH 44195, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Germline High Risk Cancer Focus Group, Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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18
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Alfahad D, Alharethi S, Alharbi B, Mawlood K, Dash P. PtdIns(4,5)P2 and PtdIns(3,4,5)P3 dynamics during focal adhesions assembly and disassembly in a cancer cell line. ACTA ACUST UNITED AC 2021; 44:381-392. [PMID: 33402865 PMCID: PMC7759192 DOI: 10.3906/biy-2004-108] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/27/2020] [Indexed: 01/22/2023]
Abstract
Focal adhesions (FAs) are large assemblies of proteins that mediate intracellular signals between the cytoskeleton and the extracellular matrix (ECM). The turnover of FA proteins plays a critical regulatory role in cancer cell migration. Plasma membrane lipids locally generated or broken down by different inositide kinases and phosphatase enzymes to activate and recruit proteins to specific regions in the plasma membrane. Presently, little attention has been given to the use of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) and Phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) fluorescent biosensors in order to determine the spatiotemporal organisation of PtdIns(4,5)P2 and PtdIns(3,4,5)P3 within and around or during assembly and disassembly of FAs. In this study, specific biosensors were used to detect PtdIns(4,5)P2, PtdIns(3,4,5)P3, and FAs proteins conjugated to RFP/GFP in order to monitor changes of PtdIns(4,5)P2 and PtdIns(3,4,5)P3 levels within FAs. We demonstrated that the localisation of PtdIns(4,5)P2 and PtdIns(3,4,5)P3 were moderately correlated with that of FA proteins. Furthermore, we demonstrate that local levels of PtdIns(4,5)P2 increased within FA assembly and declined within FA disassembly. However, PtdIns(3,4,5)P3 levels remained constant within FAs assembly and disassembly. In conclusion, this study shows that PtdIns(4,5)P2 and PtdIns(3,4,5)P3 localised in FAs may be regulated differently during FA assembly and disassembly.
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Affiliation(s)
- Dhurgham Alfahad
- Department of Pathological Analysis, College of Science, Thi-Qar University, Thi-Qar Iraq
| | - Salem Alharethi
- Department of Biological Science, College of Arts and Science, Najran University, Najran Saudi Arabia
| | - Bandar Alharbi
- Department of Clinical Laboratory Sciences, College of Applied Medical Science, University of Hail, Hail Saudi Arabia
| | - Khatab Mawlood
- Department of Clinical Laboratory Sciences, College of Applied Medical Science, University of Hail, Hail Saudi Arabia
| | - Philip Dash
- Department of Pathological Analysis, College of Science, Thi-Qar University, Thi-Qar Iraq.,Department of Biomedical Sciences, School of Biological Sciences, University of Reading, Reading United Kingdom
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19
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Kato T, Yamada T, Nakamura H, Igarashi A, Anders RA, Sesaki H, Iijima M. The Loss of Nuclear PTEN Increases Tumorigenesis in a Preclinical Mouse Model for Hepatocellular Carcinoma. iScience 2020; 23:101548. [PMID: 33083717 PMCID: PMC7516300 DOI: 10.1016/j.isci.2020.101548] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/16/2020] [Accepted: 09/07/2020] [Indexed: 02/07/2023] Open
Abstract
The PTEN gene is highly mutated in many cancers, including hepatocellular carcinoma. The PTEN protein is located at different subcellular regions-PTEN at the plasma membrane suppresses PI3-kinase signaling in cell growth, whereas PTEN in the nucleus maintains genome integrity. Here, using nuclear PTEN-deficient mice, we analyzed the role of PTEN in the nucleus in hepatocellular carcinoma that is induced by carcinogen and oxidative stress-producing hepatotoxin. Upon oxidative stress, PTEN was accumulated in the nucleus of the liver, and this accumulation promoted repair of DNA damage in wild-type mice. In contrast, nuclear PTEN-deficient mice had increased DNA damage and accelerated hepatocellular carcinoma formation. Both basal and oxidative stress-induced localization of PTEN in the nucleus require ubiquitination of lysine 13 in PTEN. Taken together, these data suggest the critical role of nuclear PTEN in the protection from DNA damage and tumorigenesis in vivo.
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Affiliation(s)
- Takashi Kato
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tatsuya Yamada
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hideki Nakamura
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Atsushi Igarashi
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Robert A. Anders
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Corresponding author
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20
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Posttranslational Regulation and Conformational Plasticity of PTEN. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a036095. [PMID: 31932468 DOI: 10.1101/cshperspect.a036095] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor that is frequently down-modulated in human cancer. PTEN inhibits the phosphatidylinositol 3-phosphate kinase (PI3K)/AKT pathway through its lipid phosphatase activity. Multiple PI3K/AKT-independent actions of PTEN, protein-phosphatase activities and functions within the nucleus have also been described. PTEN, therefore, regulates many cellular processes including cell proliferation, survival, genomic integrity, polarity, migration, and invasion. Even a modest decrease in the functional dose of PTEN may promote cancer development. Understanding the molecular and cellular mechanisms that regulate PTEN protein levels and function, and how these may go awry in cancer contexts, is, therefore, key to fully understanding the role of PTEN in tumorigenesis. Here, we discuss current knowledge on posttranslational control and conformational plasticity of PTEN, as well as therapeutic possibilities toward reestablishment of PTEN tumor-suppressor activity in cancer.
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21
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Egbe E, Levy CW, Tabernero L. Computational and structure-guided design of phosphoinositide substrate specificity into the tyrosine specific LMW-PTP enzyme. PLoS One 2020; 15:e0235133. [PMID: 32584877 PMCID: PMC7316235 DOI: 10.1371/journal.pone.0235133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/09/2020] [Indexed: 11/23/2022] Open
Abstract
We have used a combination of computational and structure-based redesign of the low molecular weight protein tyrosine phosphatase, LMW-PTP, to create new activity towards phosphoinositide substrates for which the wild-type enzyme had little or no activity. The redesigned enzymes retain catalytic activity despite residue alterations in the active site, and kinetic experiments confirmed specificity for up to four phosphoinositide substrates. Changes in the shape and overall volume of the active site where critical to facilitate access of the new substrates for catalysis. The kinetics data suggest that both the position and the combination of amino acid mutations are important for specificity towards the phosphoinositide substrates. The introduction of basic residues proved essential to establish new interactions with the multiple phosphate groups in the inositol head, thus promoting catalytically productive complexes. The crystallographic structures of the top-ranking designs confirmed the computational predictions and showed that residue substitutions do not alter the overall folding of the phosphatase or the conformation of the active site P-loop. The engineered LMW-PTP mutants with new activities can be useful reagents in investigating cell signalling pathways and offer the potential for therapeutic applications.
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Affiliation(s)
- Eyong Egbe
- School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, England, United Kingdom
| | - Colin W Levy
- School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, England, United Kingdom
| | - Lydia Tabernero
- School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, England, United Kingdom
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22
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Cheng Y, Felix B, Othmer HG. The Roles of Signaling in Cytoskeletal Changes, Random Movement, Direction-Sensing and Polarization of Eukaryotic Cells. Cells 2020; 9:E1437. [PMID: 32531876 PMCID: PMC7348768 DOI: 10.3390/cells9061437] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 12/21/2022] Open
Abstract
Movement of cells and tissues is essential at various stages during the lifetime of an organism, including morphogenesis in early development, in the immune response to pathogens, and during wound-healing and tissue regeneration. Individual cells are able to move in a variety of microenvironments (MEs) (A glossary of the acronyms used herein is given at the end) by suitably adapting both their shape and how they transmit force to the ME, but how cells translate environmental signals into the forces that shape them and enable them to move is poorly understood. While many of the networks involved in signal detection, transduction and movement have been characterized, how intracellular signals control re-building of the cyctoskeleton to enable movement is not understood. In this review we discuss recent advances in our understanding of signal transduction networks related to direction-sensing and movement, and some of the problems that remain to be solved.
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Affiliation(s)
- Yougan Cheng
- Bristol Myers Squibb, Route 206 & Province Line Road, Princeton, NJ 08543, USA;
| | - Bryan Felix
- School of Mathematics, University of Minnesota, Minneapolis, MN 55445, USA;
| | - Hans G. Othmer
- School of Mathematics, University of Minnesota, Minneapolis, MN 55445, USA;
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23
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Henager SH, Henriquez S, Dempsey DR, Cole PA. Analysis of Site-Specific Phosphorylation of PTEN by Using Enzyme-Catalyzed Expressed Protein Ligation. Chembiochem 2020; 21:64-68. [PMID: 31206229 PMCID: PMC7012368 DOI: 10.1002/cbic.201900316] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Indexed: 01/05/2023]
Abstract
The activity and localization of PTEN, a tumor suppressor lipid phosphatase that converts the phospholipid PIP3 to PIP2, is governed in part by phosphorylation on a cluster of four Ser and Thr residues near the C terminus. Prior enzymatic characterization of the four monophosphorylated (1p) PTENs by using classical expressed protein ligation (EPL) was complicated by the inclusion of a non-native Cys at the ligation junction (aa379), which may alter the properties of the semisynthetic protein. Here, we apply subtiligase-mediated EPL to create wt 1p-PTENs. These PTENs are more autoinhibited than previously appreciated, consistent with the role of Tyr379 in driving autoinhibition. Alkaline phosphatase sensitivity analysis revealed that these autoinhibited 1p conformations are kinetically labile. In contrast to the Cys mutant 1p-PTENs, which are poorly recognized by an anti-phospho-PTEN antibody, three of the four wt 1p-PTENs are recognized by a commonly used anti-phospho-PTEN antibody.
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Affiliation(s)
- Samuel H Henager
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Stephanie Henriquez
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Daniel R Dempsey
- Division of Genetics, Departments of Medicine and Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Brigham and Women's Hospital, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Philip A Cole
- Division of Genetics, Departments of Medicine and Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Brigham and Women's Hospital, 25 Shattuck Street, Boston, MA, 02115, USA
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24
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Fernández-Acero T, Bertalmio E, Luna S, Mingo J, Bravo-Plaza I, Rodríguez-Escudero I, Molina M, Pulido R, Cid VJ. Expression of Human PTEN-L in a Yeast Heterologous Model Unveils Specific N-Terminal Motifs Controlling PTEN-L Subcellular Localization and Function. Cells 2019; 8:cells8121512. [PMID: 31779149 PMCID: PMC6952770 DOI: 10.3390/cells8121512] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/21/2019] [Accepted: 11/22/2019] [Indexed: 12/21/2022] Open
Abstract
The tumour suppressor PTEN is frequently downregulated, mutated or lost in several types of tumours and congenital disorders including PHTS (PTEN Hamartoma Tumour Syndrome) and ASD (Autism Spectrum Disorder). PTEN is a lipid phosphatase whose activity over the lipid messenger PIP3 counteracts the stimulation of the oncogenic phosphatidylinositol 3-kinase (PI3K) pathway. Recently, several extended versions of PTEN produced in the cell by alternative translation initiation have been described, among which, PTEN-L and PTEN-M represent the longest isoforms. We previously developed a humanized yeast model in which the expression of PI3K in Saccharomyces cerevisiae led to growth inhibition that could be suppressed by co-expression of PTEN. Here, we show that the expression of PTEN-L and PTEN-M in yeast results in robust counteracting of PI3K-dependent growth inhibition. N-terminally tagged GFP-PTEN-L was sharply localized at the yeast plasma membrane. Point mutations of a putative membrane-binding helix located at the PTEN-L extension or its deletion shifted localization to nuclear. Also, a shift from plasma membrane to nucleus was observed in mutants at basic amino acid clusters at the PIP2-binding motif, and at the Cα2 and CBR3 loops at the C2 domain. In contrast, C-terminally tagged PTEN-L-GFP displayed mitochondrial localization in yeast, which was shifted to plasma membrane by removing the first 22 PTEN-L residues. Our results suggest an important role of the N-terminal extension of alternative PTEN isoforms on their spatial and functional regulation.
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Affiliation(s)
- Teresa Fernández-Acero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Eleonora Bertalmio
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Sandra Luna
- Instituto de Investigación Sanitaria Biocruces Bizkaia, 48903 Barakaldo, Spain; (S.L.); (J.M.)
| | - Janire Mingo
- Instituto de Investigación Sanitaria Biocruces Bizkaia, 48903 Barakaldo, Spain; (S.L.); (J.M.)
| | - Ignacio Bravo-Plaza
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Isabel Rodríguez-Escudero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
| | - Rafael Pulido
- Instituto de Investigación Sanitaria Biocruces Bizkaia, 48903 Barakaldo, Spain; (S.L.); (J.M.)
- IKERBASQUE, Fundación Vasca para la Ciencia, 48011 Bilbao, Spain
- Correspondence: (R.P.); (V.J.C.)
| | - Víctor J. Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM) & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS). Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain; (T.F.-A.); (E.B.); (I.B.-P.); (I.R.-E.); (M.M.)
- Correspondence: (R.P.); (V.J.C.)
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Hasle N, Matreyek KA, Fowler DM. The Impact of Genetic Variants on PTEN Molecular Functions and Cellular Phenotypes. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a036228. [PMID: 31451538 DOI: 10.1101/cshperspect.a036228] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Phosphatase and tensin homolog (PTEN) is a tumor suppressor that directly regulates a diverse array of cellular phenotypes, including growth, migration, morphology, and genome stability. How a single protein impacts so many important cellular processes remains a fascinating question. This question has been partially resolved by the characterization of a slew of missense variants that alter or eliminate PTEN's various molecular functions, including its enzymatic activity, subcellular localization, and posttranslational modifications. Here, we review what is known about how PTEN variants impact molecular function and, consequently, cellular phenotype. In particular, we highlight eight informative "sentinel variants" that abrogate distinct molecular functions of PTEN. We consider two published massively parallel assays of variant effect that measured the effect of thousands of PTEN variants on protein abundance and enzymatic activity. Finally, we discuss how characterization of clinically ascertained variants, establishment of clinical sequencing databases, and massively parallel assays of variant effect yield complementary datasets for dissecting PTEN's role in disease.
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Affiliation(s)
- Nicholas Hasle
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Kenneth A Matreyek
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Douglas M Fowler
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA.,Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA.,Genetic Networks Program, CIFAR, Toronto, Ontario, M5G 1M1, Canada
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26
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Han CY, Patten DA, Lee SG, Parks RJ, Chan DW, Harper M, Tsang BK. p53 Promotes chemoresponsiveness by regulating hexokinase II gene transcription and metabolic reprogramming in epithelial ovarian cancer. Mol Carcinog 2019; 58:2161-2174. [DOI: 10.1002/mc.23106] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 08/16/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Chae Young Han
- Department of Obstetrics & Gynecology and Cellular & Molecular MedicineUniversity of Ottawa; Chronic Disease Program, Ottawa Hospital Research Institute Ottawa Ontario Canada
| | - David A. Patten
- Department of Biochemistry, Microbiology and ImmunologyUniversity of Ottawa, Institute of Systems Biology Ottawa Ontario Canada
| | - Seung Gee Lee
- Department of Obstetrics & Gynecology and Cellular & Molecular MedicineUniversity of Ottawa; Chronic Disease Program, Ottawa Hospital Research Institute Ottawa Ontario Canada
| | - Robin J. Parks
- Department of Biochemistry, Microbiology & ImmunologyUniversity of Ottawa and Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa Ontario Canada
| | - David W. Chan
- Department of Obstetrics and GynecologyThe University of Hong Kong Hong Kong SAR P.R. China
| | - Mary‐Ellen Harper
- Department of Biochemistry, Microbiology and ImmunologyUniversity of Ottawa, Institute of Systems Biology Ottawa Ontario Canada
| | - Benjamin K. Tsang
- Department of Obstetrics & Gynecology and Cellular & Molecular MedicineUniversity of Ottawa; Chronic Disease Program, Ottawa Hospital Research Institute Ottawa Ontario Canada
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27
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Multifaceted Regulation of PTEN Subcellular Distributions and Biological Functions. Cancers (Basel) 2019; 11:cancers11091247. [PMID: 31454965 PMCID: PMC6770588 DOI: 10.3390/cancers11091247] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/15/2019] [Accepted: 08/19/2019] [Indexed: 12/19/2022] Open
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene frequently found to be inactivated in over 30% of human cancers. PTEN encodes a 54-kDa lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase pathway involved in the promotion of multiple pro-tumorigenic phenotypes. Although the PTEN protein plays a pivotal role in carcinogenesis, cumulative evidence has implicated it as a key signaling molecule in several other diseases as well, such as diabetes, Alzheimer's disease, and autism spectrum disorders. This finding suggests that diverse cell types, especially differentiated cells, express PTEN. At the cellular level, PTEN is widely distributed in all subcellular compartments and organelles. Surprisingly, the cytoplasmic compartment, not the plasma membrane, is the predominant subcellular location of PTEN. More recently, the finding of a secreted 'long' isoform of PTEN and the presence of PTEN in the cell nucleus further revealed unexpected biological functions of this multifaceted molecule. At the regulatory level, PTEN activity, stability, and subcellular distribution are modulated by a fascinating array of post-translational modification events, including phosphorylation, ubiquitination, and sumoylation. Dysregulation of these regulatory mechanisms has been observed in various human diseases. In this review, we provide an up-to-date overview of the knowledge gained in the last decade on how different functional domains of PTEN regulate its biological functions, with special emphasis on its subcellular distribution. This review also highlights the findings of published studies that have reported how mutational alterations in specific PTEN domains can lead to pathogenesis in humans.
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Yehia L, Ngeow J, Eng C. PTEN-opathies: from biological insights to evidence-based precision medicine. J Clin Invest 2019; 129:452-464. [PMID: 30614812 DOI: 10.1172/jci121277] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The tumor suppressor phosphatase and tensin homolog (PTEN) classically counteracts the PI3K/AKT/mTOR signaling cascade. Germline pathogenic PTEN mutations cause PTEN hamartoma tumor syndrome (PHTS), featuring various benign and malignant tumors, as well as neurodevelopmental disorders such as autism spectrum disorder. Germline and somatic mosaic mutations in genes encoding components of the PI3K/AKT/mTOR pathway downstream of PTEN predispose to syndromes with partially overlapping clinical features, termed the "PTEN-opathies." Experimental models of PTEN pathway disruption uncover the molecular and cellular processes influencing clinical phenotypic manifestations. Such insights not only teach us about biological mechanisms in states of health and disease, but also enable more accurate gene-informed cancer risk assessment, medical management, and targeted therapeutics. Hence, the PTEN-opathies serve as a prototype for bedside to bench, and back to the bedside, practice of evidence-based precision medicine.
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Affiliation(s)
- Lamis Yehia
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Joanne Ngeow
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Cancer Genetics Service, Division of Medical Oncology, National Cancer Centre, Singapore.,Oncology Academic Program, Duke-NUS Graduate Medical School, Singapore
| | - Charis Eng
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.,Germline High Risk Cancer Focus Group, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, USA
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29
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Dempsey DR, Cole PA. Protein Chemical Approaches to Understanding PTEN Lipid Phosphatase Regulation. Methods Enzymol 2018; 607:405-422. [PMID: 30149868 DOI: 10.1016/bs.mie.2018.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
Since the discovery of C-tail phosphorylation of PTEN almost 20 years ago, much progress has been made in understanding its regulatory influences on the cellular function of PTEN. Phosphorylation of Ser380, Thr382, Thr383, and Ser385 drives a PTEN conformational change from an open to closed state where catalytic function is impaired, plasma membrane binding is reduced, and cellular stability is enhanced. Despite these advances, a detailed structural and mechanistic model of how these phosphorylations impact PTEN function is lacking. We discuss here several recent approaches to analyzing PTEN phosphorylation and highlight several insights that have come from this work. We also discuss remaining challenges for the PTEN regulation field and potential directions for future research.
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Affiliation(s)
- Daniel R Dempsey
- Division of Genetics, Brigham and Women's Hospital, Boston, MA, United States; Department of Medicine, Harvard Medical School, Boston, MA, United States; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States
| | - Philip A Cole
- Division of Genetics, Brigham and Women's Hospital, Boston, MA, United States; Department of Medicine, Harvard Medical School, Boston, MA, United States; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States.
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30
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Lee YR, Chen M, Pandolfi PP. The functions and regulation of the PTEN tumour suppressor: new modes and prospects. Nat Rev Mol Cell Biol 2018; 19:547-562. [DOI: 10.1038/s41580-018-0015-0] [Citation(s) in RCA: 399] [Impact Index Per Article: 66.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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31
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Malaney P, Palumbo E, Semidey-Hurtado J, Hardee J, Stanford K, Kathiriya JJ, Patel D, Tian Z, Allen-Gipson D, Davé V. PTEN Physically Interacts with and Regulates E2F1-mediated Transcription in Lung Cancer. Cell Cycle 2018; 17:947-962. [PMID: 29108454 PMCID: PMC6103743 DOI: 10.1080/15384101.2017.1388970] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 09/28/2017] [Accepted: 10/02/2017] [Indexed: 12/13/2022] Open
Abstract
PTEN phosphorylation at its C-terminal (C-tail) serine/threonine cluster negatively regulates its tumor suppressor function. However, the consequence of such inhibition and its downstream effects in driving lung cancer remain unexplored. Herein, we ascertain the molecular mechanisms by which phosphorylation compromises PTEN function, contributing to lung cancer. Replacement of the serine/threonine residues with alanine generated PTEN-4A, a phosphorylation-deficient PTEN mutant, which suppressed lung cancer cell proliferation and migration. PTEN-4A preferentially localized to the nucleus where it suppressed E2F1-mediated transcription of cell cycle genes. PTEN-4A physically interacted with the transcription factor E2F1 and associated with chromatin at gene promoters with E2F1 DNA-binding sites, a likely mechanism for its transcriptional suppression function. Deletion analysis revealed that the C2 domain of PTEN was indispensable for suppression of E2F1-mediated transcription. Further, we uncovered cancer-associated C2 domain mutant proteins that had lost their ability to suppress E2F1-mediated transcription, supporting the concept that these mutations are oncogenic in patients. Consistent with these findings, we observed increased PTEN phosphorylation and reduced nuclear PTEN levels in lung cancer patient samples establishing phosphorylation as a bona fide inactivation mechanism for PTEN in lung cancer. Thus, use of small molecule inhibitors that hinder PTEN phosphorylation is a plausible approach to activate PTEN function in the treatment of lung cancer. Abbreviations AKT V-Akt Murine Thymoma Viral Oncogene CA Cancer adjacent CDK1 Cyclin dependent kinase 1 CENPC-C Centromere Protein C ChIP Chromatin Immunoprecipitation co-IP Co-immunoprecipitation COSMIC Catalog of Somatic Mutations In Cancer CREB cAMP Responsive Element Binding Protein C-tail Carboxy terminal tail E2F1 E2F Transcription Factor 1 ECIS Electric Cell-substrate Impedance Sensing EGFR Epidermal Growth Factor Receptor GSI Gamma Secretase Inhibitor HDAC1 Histone Deacetylase 1 HP1 Heterochromatin protein 1 KAP1/TRIM28 KRAB-Associated Protein 1/Tripartite Motif Containing 28 MAF1 Repressor of RNA polymerase III transcription MAF1 homolog MCM2 Minichromosome Maintenance Complex Component 2 miRNA micro RNA MTF1 Metal-Regulatory Transcription Factor 1 PARP Poly(ADP-Ribose) Polymerase PD-1 Programmed Cell Death 1 PD-L1 Programmed Cell Death 1 Ligand 1 PI3K Phosphatidylinositol-4,5-Bisphosphate 3-Kinase PLK Polo-like Kinase pPTEN Phosphorylated PTEN PTEN Phosphatase and Tensin Homolog deleted on chromosome ten PTM Post Translational Modification Rad51 RAD51 Recombinase Rad52 RAD52 Recombinase RPA1 Replication protein A SILAC Stable Isotope Labeling with Amino Acids in Cell Culture SRF Serum Response Factor TKI Tyrosine Kinase inhbitors TMA Tissue Microarray TOP2A DNA Topoisomerase 2A.
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Affiliation(s)
- Prerna Malaney
- Department of Pathology and Cell Biology, Morsani College of Medicine
| | - Emily Palumbo
- Department of Pathology and Cell Biology, Morsani College of Medicine
| | | | - Jamaal Hardee
- Department of Pathology and Cell Biology, Morsani College of Medicine
| | | | | | - Deepal Patel
- Department of Pathology and Cell Biology, Morsani College of Medicine
| | - Zhi Tian
- College of Pharmacy, University of South Florida, Tampa, FL 33612, United States
| | - Diane Allen-Gipson
- College of Pharmacy, University of South Florida, Tampa, FL 33612, United States
| | - Vrushank Davé
- Department of Pathology and Cell Biology, Morsani College of Medicine
- Lung Cancer Center of Excellence, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, United States
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32
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Igarashi A, Itoh K, Yamada T, Adachi Y, Kato T, Murata D, Sesaki H, Iijima M. Nuclear PTEN deficiency causes microcephaly with decreased neuronal soma size and increased seizure susceptibility. J Biol Chem 2018; 293:9292-9300. [PMID: 29735527 DOI: 10.1074/jbc.ra118.002356] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/20/2018] [Indexed: 12/25/2022] Open
Abstract
Defects in phosphatase and tensin homolog (PTEN) are associated with neurological disorders and tumors. PTEN functions at two primary intracellular locations: the plasma membrane and the nucleus. At the membrane, PTEN functions as a phosphatidylinositol (3,4,5)-trisphosphate phosphatase and suppresses PI 3-kinase signaling that drives cell growth and tumorigenesis. However, the in vivo function of nuclear PTEN is unclear. Here, using CRISPR/Cas9, we generated a mouse model in which PTEN levels in the nucleus are decreased. Nuclear PTEN-deficient mice were born with microcephaly and maintained a small brain during adulthood. The size of neuronal soma was significantly smaller in the cerebellum, cerebral cortex, and hippocampus. Also, these mice were prone to seizure. No changes in PI 3-kinase signaling were observed. By contrast, the size of other organs was unaffected. Therefore, nuclear PTEN is essential for the health of the brain by promoting the growth of neuronal soma size during development.
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Affiliation(s)
- Atsushi Igarashi
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Kie Itoh
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Tatsuya Yamada
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Yoshihiro Adachi
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Takashi Kato
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Daisuke Murata
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Hiromi Sesaki
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Miho Iijima
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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33
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A pathogenic role for germline PTEN variants which accumulate into the nucleus. Eur J Hum Genet 2018; 26:1180-1187. [PMID: 29706633 DOI: 10.1038/s41431-018-0155-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/27/2018] [Accepted: 03/30/2018] [Indexed: 11/08/2022] Open
Abstract
The PTEN gene encodes a master regulator protein that exerts essential functions both in the cytoplasm and in the nucleus. PTEN is mutated in the germline of both patients with heterogeneous tumor syndromic diseases, categorized as PTEN hamartoma tumor syndrome (PHTS), and a group affected with autism spectrum disorders (ASD). Previous studies have unveiled the functional heterogeneity of PTEN variants found in both patient cohorts, making functional studies necessary to provide mechanistic insights related to their pathogenicity. Here, we have functionally characterized a PTEN missense variant [c.49C>G; p.(Gln17Glu); Q17E] associated to both PHTS and ASD patients. The PTEN Q17E variant displayed partially reduced PIP3-catalytic activity and normal stability in cells, as shown using S. cerevisiae and mammalian cell experimental models. Remarkably, PTEN Q17E accumulated in the nucleus, in a process involving the PTEN N-terminal nuclear localization sequence. The analysis of additional germline-associated PTEN N-terminal variants illustrated the existence of a PTEN N-terminal region whose targeting in disease causes PTEN nuclear accumulation, in parallel with defects in PIP3-catalytic activity in cells. Our findings highlight the frequent occurrence of PTEN gene mutations targeting PTEN N-terminus whose pathogenicity may be related, at least in part, with the retention of PTEN in the nucleus. This could be important for the implementation of precision therapies for patients with alterations in the PTEN pathway.
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34
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Rosselli-Murai LK, Yates JA, Yoshida S, Bourg J, Ho KKY, White M, Prisby J, Tan X, Altemus M, Bao L, Wu ZF, Veatch SL, Swanson JA, Merajver SD, Liu AP. Loss of PTEN promotes formation of signaling-capable clathrin-coated pits. J Cell Sci 2018; 131:jcs.208926. [PMID: 29588397 DOI: 10.1242/jcs.208926] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 03/19/2018] [Indexed: 12/19/2022] Open
Abstract
Defective endocytosis and vesicular trafficking of signaling receptors has recently emerged as a multifaceted hallmark of malignant cells. Clathrin-coated pits (CCPs) display highly heterogeneous dynamics on the plasma membrane where they can take from 20 s to over 1 min to form cytosolic coated vesicles. Despite the large number of cargo molecules that traffic through CCPs, it is not well understood whether signaling receptors activated in cancer, such as epidermal growth factor receptor (EGFR), are regulated through a specific subset of CCPs. The signaling lipid phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3], which is dephosphorylated by phosphatase and tensin homolog (PTEN), is a potent tumorigenic signaling lipid. By using total internal reflection fluorescence microscopy and automated tracking and detection of CCPs, we found that EGF-bound EGFR and PTEN are enriched in a distinct subset of short-lived CCPs that correspond with clathrin-dependent EGF-induced signaling. We demonstrated that PTEN plays a role in the regulation of CCP dynamics. Furthermore, increased PI(3,4,5)P3 resulted in higher proportion of short-lived CCPs, an effect that recapitulates PTEN deletion. Altogether, our findings provide evidence for the existence of short-lived 'signaling-capable' CCPs.
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Affiliation(s)
| | - Joel A Yates
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Sei Yoshida
- Department of Microbiology and Immunology of Michigan Medical School, University of Michigan, Ann Arbor, MI 48109-5620, USA
| | - Julia Bourg
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Kenneth K Y Ho
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan White
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Julia Prisby
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xinyu Tan
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan Altemus
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA.,Cancer Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Liwei Bao
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Zhi-Fen Wu
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Sarah L Veatch
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Joel A Swanson
- Department of Microbiology and Immunology of Michigan Medical School, University of Michigan, Ann Arbor, MI 48109-5620, USA
| | - Sofia D Merajver
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA .,Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA .,Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA.,Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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35
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Targeting PTEN in Colorectal Cancers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1110:55-73. [DOI: 10.1007/978-3-030-02771-1_5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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36
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McLoughlin NM, Mueller C, Grossmann TN. The Therapeutic Potential of PTEN Modulation: Targeting Strategies from Gene to Protein. Cell Chem Biol 2018; 25:19-29. [DOI: 10.1016/j.chembiol.2017.10.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/05/2017] [Accepted: 10/23/2017] [Indexed: 01/04/2023]
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37
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Lavictoire SJ, Gont A, Julian LM, Stanford WL, Vlasschaert C, Gray DA, Jomaa D, Lorimer IAJ. Engineering PTEN-L for Cell-Mediated Delivery. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 9:12-22. [PMID: 29255742 PMCID: PMC5725211 DOI: 10.1016/j.omtm.2017.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 11/14/2017] [Indexed: 01/04/2023]
Abstract
The tumor suppressor PTEN is frequently inactivated in glioblastoma. PTEN-L is a long form of PTEN produced by translation from an alternate upstream start codon. Unlike PTEN, PTEN-L has a signal sequence and a tract of six arginine residues that allow PTEN-L to be secreted from cells and be taken up by neighboring cells. This suggests that PTEN-L could be used as a therapeutic to restore PTEN activity. However, effective delivery of therapeutic proteins to treat CNS cancers such as glioblastoma is challenging. One method under evaluation is cell-mediated therapy, where cells with tumor-homing abilities such as neural stem cells are genetically modified to express a therapeutic protein. Here, we have developed a version of PTEN-L that is engineered for enhanced cell-mediated delivery. This was accomplished by replacement of the native leader sequence of PTEN-L with a leader sequence from human light-chain immunoglobulin G (IgG). This version of PTEN-L showed increased secretion and an increased ability to transfer to neighboring cells. Neural stem cells derived from human fibroblasts could be modified to express this version of PTEN-L and were able to deliver catalytically active light-chain leader PTEN-L (lclPTEN-L) to neighboring glioblastoma cells.
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Affiliation(s)
- Sylvie J Lavictoire
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
| | - Alexander Gont
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Lisa M Julian
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
| | - William L Stanford
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Caitlyn Vlasschaert
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Douglas A Gray
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Danny Jomaa
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Ian A J Lorimer
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,Department of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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38
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Positive diversifying selection is a pervasive adaptive force throughout the Drosophila radiation. Mol Phylogenet Evol 2017; 112:230-243. [DOI: 10.1016/j.ympev.2017.04.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 04/26/2017] [Accepted: 04/26/2017] [Indexed: 01/02/2023]
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39
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TGF-β induces phosphorylation of phosphatase and tensin homolog: implications for fibrosis of the trabecular meshwork tissue in glaucoma. Sci Rep 2017; 7:812. [PMID: 28400560 PMCID: PMC5429747 DOI: 10.1038/s41598-017-00845-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 03/16/2017] [Indexed: 01/06/2023] Open
Abstract
Fundamental cell signaling mechanisms that regulate dynamic remodeling of the extracellular matrix (ECM) in mechanically loaded tissues are not yet clearly understood. Trabecular meshwork (TM) tissue in the eye is under constant mechanical stress and continuous remodeling of ECM is crucial to maintain normal aqueous humor drainage and intraocular pressure (IOP). However, excessive ECM remodeling can cause fibrosis of the TM as in primary open-angle glaucoma (POAG) patients, and is characterized by increased resistance to aqueous humor drainage, elevated IOP, optic nerve degeneration and blindness. Increased levels of active transforming growth factor-β2 (TGF-β2) in the aqueous humor is the main cause of fibrosis of TM in POAG patients. Herein, we report a novel finding that, in TM cells, TGF-β-induced increase in collagen expression is associated with phosphorylation of phosphatase and tensin homolog (PTEN) at residues Ser380/Thr382/383. Exogenous overexpression of a mutated form of PTEN with enhanced phosphatase activity prevented the TGF-β-induced collagen expression by TM cells. We propose that rapid alteration of PTEN activity through changes in its phosphorylation status could uniquely regulate the continuous remodeling of ECM in the normal TM. Modulating PTEN activity may have high therapeutic potential to alleviating the fibrosis of TM in POAG patients.
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40
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Yang JM, Schiapparelli P, Nguyen HN, Igarashi A, Zhang Q, Abbadi S, Amzel LM, Sesaki H, Quiñones-Hinojosa A, Iijima M. Characterization of PTEN mutations in brain cancer reveals that pten mono-ubiquitination promotes protein stability and nuclear localization. Oncogene 2017; 36:3673-3685. [PMID: 28263967 PMCID: PMC5491373 DOI: 10.1038/onc.2016.493] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 11/21/2016] [Accepted: 11/29/2016] [Indexed: 12/26/2022]
Abstract
PTEN is a PIP3 phosphatase that antagonizes oncogenic PI3-kinase signalling. Due to its critical role in suppressing the potent signalling pathway, it is one of the most mutated tumour suppressors, especially in brain tumours. It is generally thought that PTEN deficiencies predominantly result from either loss of expression or enzymatic activity. By analysing PTEN in malignant glioblastoma primary cells derived from 16 of our patients, we report mutations that block localization of PTEN at the plasma membrane and nucleus without affecting lipid phosphatase activity. Cellular and biochemical analyses as well as structural modelling revealed that two mutations disrupt intramolecular interaction of PTEN and open its conformation, enhancing polyubiquitination of PTEN and decreasing protein stability. Moreover, promoting mono-ubiquitination increases protein stability and nuclear localization of mutant PTEN. Thus, our findings provide a molecular mechanism for cancer-associated PTEN defects and may lead to a brain cancer treatment that targets PTEN mono-ubiquitination.
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Affiliation(s)
- Jr-M Yang
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - P Schiapparelli
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - H-N Nguyen
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A Igarashi
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Q Zhang
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - S Abbadi
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - L M Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - H Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A Quiñones-Hinojosa
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - M Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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41
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Palliyaguru DL, Chartoumpekis DV, Wakabayashi N, Skoko JJ, Yagishita Y, Singh SV, Kensler TW. Withaferin A induces Nrf2-dependent protection against liver injury: Role of Keap1-independent mechanisms. Free Radic Biol Med 2016; 101:116-128. [PMID: 27717869 PMCID: PMC5154810 DOI: 10.1016/j.freeradbiomed.2016.10.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/28/2016] [Accepted: 10/02/2016] [Indexed: 12/30/2022]
Abstract
Small molecules of plant origin offer presumptively safe opportunities to prevent carcinogenesis, mutagenesis and other forms of toxicity in humans. However, the mechanisms of action of such plant-based agents remain largely unknown. In recent years the stress responsive transcription factor Nrf2 has been validated as a target for disease chemoprevention. Withania somnifera (WS) is a herb used in Ayurveda (an ancient form of medicine in South Asia). In the recent past, withanolides isolated from WS, such as Withaferin A (WA) have been demonstrated to be preventive and therapeutic against multiple diseases in experimental models. The goals of this study are to evaluate withanolides such as WA as well as Withania somnifera root extract as inducers of Nrf2 signaling, to probe the underlying signaling mechanism of WA and to determine whether prevention of acetaminophen (APAP)-induced hepatic toxicity in mice by WA occurs in an Nrf2-dependent manner. We observed that WA profoundly protects wild-type mice but not Nrf2-disrupted mice against APAP hepatotoxicity. WA is a potent inducer of Nrf2-dependent cytoprotective enzyme expression both in vivo and in vitro. Unexpectedly, WA induces Nrf2 signaling at least in part, in a Keap1-independent, Pten/Pi3k/Akt-dependent manner in comparison to prototypical Nrf2 inducers, sulforaphane and CDDO-Im. The identification of WA as an Nrf2 inducer that can signal through a non-canonical, Keap1-independent pathway provides an opportunity to evaluate the role of other regulatory partners of Nrf2 in the dietary and pharmacological induction of Nrf2-mediated cytoprotection.
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Affiliation(s)
- Dushani L Palliyaguru
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dionysios V Chartoumpekis
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Nobunao Wakabayashi
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - John J Skoko
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yoko Yagishita
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shivendra V Singh
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Thomas W Kensler
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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42
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Gupta A, Leslie NR. Controlling PTEN (Phosphatase and Tensin Homolog) Stability: A DOMINANT ROLE FOR LYSINE 66. J Biol Chem 2016; 291:18465-73. [PMID: 27405757 DOI: 10.1074/jbc.m116.727750] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Indexed: 11/06/2022] Open
Abstract
Phosphatase and tensin homolog (PTEN) is a phosphoinositide lipid phosphatase and one of the most frequently disrupted tumor suppressors in many forms of cancer, with even small reductions in the expression levels of PTEN promoting cancer development. Although the post-translational ubiquitination of PTEN can control its stability, activity, and localization, a detailed understanding of how PTEN ubiquitination integrates with other cellular regulatory processes and may be dysregulated in cancer has been hampered by a poor understanding of the significance of ubiquitination at individual sites. Here we show that Lys(66) is not required for cellular activity, yet dominates over other PTEN ubiquitination sites in the regulation of protein stability. Notably, combined mutation of other sites (Lys(13), Lys(80), and Lys(289)) has relatively little effect on protein expression, protein stability, or PTEN polyubiquitination. The present work identifies a key role for Lys(66) in the regulation of PTEN expression and provides both an opportunity to improve the stability of PTEN as a protein therapy and a mechanistic basis for efforts to stabilize endogenous PTEN.
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Affiliation(s)
- Amit Gupta
- From the Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, James Nasmyth Building, Riccarton Campus, Edinburgh EH14 4AS, United Kingdom
| | - Nicholas R Leslie
- From the Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, James Nasmyth Building, Riccarton Campus, Edinburgh EH14 4AS, United Kingdom
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43
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Kilinc D, Dennis CL, Lee GU. Bio-Nano-Magnetic Materials for Localized Mechanochemical Stimulation of Cell Growth and Death. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:5672-80. [PMID: 26780501 PMCID: PMC5536250 DOI: 10.1002/adma.201504845] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/12/2015] [Indexed: 05/16/2023]
Abstract
Magnetic nanoparticles are promising new tools for therapeutic applications, such as magnetic nanoparticle hyperthermia therapy and targeted drug delivery. Recent in vitro studies have demonstrated that a force application with magnetic tweezers can also affect cell fate, suggesting a therapeutic potential for magnetically modulated mechanical stimulation. The magnetic properties of nanoparticles that induce physical responses and the subtle responses that result from mechanically induced membrane damage and/or intracellular signaling are evaluated. Magnetic particles with various physical, geometric, and magnetic properties and specific functionalization can now be used to apply mechanical force to specific regions of cells, which permit the modulation of cellular behavior through the use of spatially and time controlled magnetic fields. On one hand, mechanochemical stimulation has been used to direct the outgrowth on neuronal growth cones, indicating a therapeutic potential for neural repair. On the other hand, it has been used to kill cancer cells that preferentially express specific receptors. Advances made in the synthesis and characterization of magnetic nanomaterials and a better understanding of cellular mechanotransduction mechanisms may support the translation of mechanochemical stimulation into the clinic as an emerging therapeutic approach.
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Affiliation(s)
- Devrim Kilinc
- Bionanosciences Lab, School of Chemistry and Chemical Biology, UCD
Conway Institute of Biomolecular and Biomedical Research, University College Dublin,
Belfield, Dublin 4, Ireland
| | - Cindi L. Dennis
- Material Measurement Laboratory, National Institute of Standards and
Technology, 100 Bureau Drive, Gaithersburg, MD 20899–8552, USA
| | - Gil U. Lee
- Bionanosciences Lab, School of Chemistry and Chemical Biology, UCD
Conway Institute of Biomolecular and Biomedical Research, University College Dublin,
Belfield, Dublin 4, Ireland
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44
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Chen Z, Dempsey DR, Thomas SN, Hayward D, Bolduc DM, Cole PA. Molecular Features of Phosphatase and Tensin Homolog (PTEN) Regulation by C-terminal Phosphorylation. J Biol Chem 2016; 291:14160-14169. [PMID: 27226612 DOI: 10.1074/jbc.m116.728980] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Indexed: 12/27/2022] Open
Abstract
PTEN is a tumor suppressor that functions to negatively regulate the PI3K/AKT pathway as the lipid phosphatase for phosphatidylinositol 3,4,5-triphosphate. Phosphorylation of a cluster of Ser/Thr residues (amino acids 380-385) on the C-terminal tail serves to alter the conformational state of PTEN from an open active state to a closed inhibited state, resulting in a reduction of plasma membrane localization and inhibition of enzyme activity. The relative contribution of each phosphorylation site to PTEN autoinhibition and the structural basis for the conformational closure is still unclear. To further the structural understanding of PTEN regulation by C-terminal tail phosphorylation, we used protein semisynthesis to insert stoichiometric and site-specific phospho-Ser/Thr(s) in the C-terminal tail of PTEN. Additionally, we employed photo-cross-linking to map the intramolecular PTEN interactions of the phospho-tail. Systematic evaluation of the PTEN C-tail phospho-cluster showed autoinhibition, and conformational closure was influenced by the aggregate effect of multiple phospho-sites rather than dominated by a single phosphorylation site. Moreover, photo-cross-linking suggested a direct interaction between the PTEN C-tail and a segment in the N-terminal region of the catalytic domain. Mutagenesis experiments provided additional insights into how the PTEN phospho-tail interacts with both the C2 and catalytic domains.
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Affiliation(s)
- Zan Chen
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205
| | - Daniel R Dempsey
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205
| | - Stefani N Thomas
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205
| | - Dawn Hayward
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205
| | - David M Bolduc
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205
| | - Philip A Cole
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205.
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45
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Stumpf M, Blokzijl-Franke S, den Hertog J. Fine-Tuning of Pten Localization and Phosphatase Activity Is Essential for Zebrafish Angiogenesis. PLoS One 2016; 11:e0154771. [PMID: 27138341 PMCID: PMC4854392 DOI: 10.1371/journal.pone.0154771] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/19/2016] [Indexed: 02/06/2023] Open
Abstract
The lipid- and protein phosphatase PTEN is an essential tumor suppressor that is highly conserved among all higher eukaryotes. As an antagonist of the PI3K/Akt cell survival and proliferation pathway, it exerts its most prominent function at the cell membrane, but (PIP3-independent) functions of nuclear PTEN have been discovered as well. PTEN subcellular localization is tightly controlled by its protein conformation. In the closed conformation, PTEN localizes predominantly to the cytoplasm. Opening up of the conformation of PTEN exposes N-terminal and C-terminal regions of the protein that are required for both interaction with the cell membrane and translocation to the nucleus. Lack of Pten leads to hyperbranching of the intersegmental vessels during zebrafish embryogenesis, which is rescued by expression of exogenous Pten. Here, we observed that expression of mutant PTEN with an open conformation rescued the hyperbranching phenotype in pten double homozygous embryos and suppressed the increased p-Akt levels that are characteristic for embryos lacking Pten. In addition, in pten mutant and wild type embryos alike, open conformation PTEN induced stalled intersegmental vessels, which fail to connect with the dorsal longitudinal anastomotic vessel. Functional hyperactivity of open conformation PTEN in comparison to wild type PTEN seems to result predominantly from its enhanced recruitment to the cell membrane. Enhanced recruitment of phosphatase inactive mutants to the membrane did not induce the stalled vessel phenotype nor did it rescue the hyperbranching phenotype in pten double homozygous embryos, indicating that PTEN phosphatase activity is indispensable for its regulatory function during angiogenesis. Taken together, our data suggest that PTEN phosphatase activity needs to be carefully fine-tuned for normal embryogenesis and that the control of its subcellular localization is a key mechanism in this process.
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Affiliation(s)
- Miriam Stumpf
- Hubrecht Institute–Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sasja Blokzijl-Franke
- Hubrecht Institute–Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeroen den Hertog
- Hubrecht Institute–Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) and University Medical Center Utrecht, Utrecht, The Netherlands
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
- * E-mail:
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46
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Abstract
The phosphatase and tensin homologue deleted on chromosome 10 (PTEN) phosphatase dephosphorylates PIP3, the lipid product of the class I PI 3-kinases, and suppresses the growth and proliferation of many cell types. It has been heavily studied, in large part due to its status as a tumour suppressor, the loss of function of which is observed through diverse mechanisms in many tumour types. Here we present a concise review of our understanding of the PTEN protein and highlight recent advances, particularly in our understanding of its localization and regulation by ubiquitination and SUMOylation.
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47
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Gómez S, López-Estepa M, Fernández FJ, Suárez T, Vega MC. Alternative Eukaryotic Expression Systems for the Production of Proteins and Protein Complexes. ADVANCED TECHNOLOGIES FOR PROTEIN COMPLEX PRODUCTION AND CHARACTERIZATION 2016; 896:167-84. [DOI: 10.1007/978-3-319-27216-0_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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48
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Abstract
PTEN subcellular localization is fundamental in the execution of the distinct PTEN biological activities, including not only its PI(3,4,5)P3 phosphatase activity when associated to membranes but also its subcellular compartment-specific interactions with regulatory and effector proteins, including those exerted in the nucleus. As a consequence, PTEN subcellular localization is tightly regulated in vivo by both intrinsic and extrinsic mechanisms. The plasma membrane/nucleus/cytoplasm partitioning of PTEN has been the focus of several studies, both from a mechanistic and from a disease-association point of view. Here, we summarize the current knowledge on PTEN plasma membrane/nucleus/cytoplasm distribution, and present subcellular fractionation, immunofluorescence, and immunohistochemical methods to study the distribution and shuttling of PTEN between these subcellular compartments.
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Affiliation(s)
- Anabel Gil
- Centro de Investigación Príncipe Felipe, Valencia, 46013, Spain
- Department of Hematology and Medical Oncology, Biomedical Research Institute INCLIVA, Valencia, 46010, Spain
| | - José I López
- Department of Pathology, Cruces University Hospital, University of the Basque Country (UPV/EHU), Barakaldo, 48903, Spain
- Biocruces Health Research Institute, Plaza de Cruces s/n, Barakaldo, Bizkaia, 48903, Spain
| | - Rafael Pulido
- Centro de Investigación Príncipe Felipe, Valencia, 46013, Spain.
- Biocruces Health Research Institute, Plaza de Cruces s/n, Barakaldo, Bizkaia, 48903, Spain.
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain.
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49
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Chia YCJ, Catimel B, Lio DSS, Ang CS, Peng B, Wu H, Zhu HJ, Cheng HC. The C-terminal tail inhibitory phosphorylation sites of PTEN regulate its intrinsic catalytic activity and the kinetics of its binding to phosphatidylinositol-4,5-bisphosphate. Arch Biochem Biophys 2015; 587:48-60. [PMID: 26471078 DOI: 10.1016/j.abb.2015.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 10/04/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Dephosphorylation of four major C-terminal tail sites and occupancy of the phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]-binding site of PTEN cooperate to activate its phospholipid phosphatase activity and facilitate its recruitment to plasma membrane. Our investigation of the mechanism by which phosphorylation of these C-terminal sites controls the PI(4,5)P2-binding affinity and catalytic activity of PTEN resulted in the following findings. First, dephosphorylation of all four sites leads to full activation; and phosphorylation of any one site significantly reduces the intrinsic catalytic activity of PTEN. These findings suggest that coordinated inhibition of the upstream protein kinases and activation of the protein phosphatases targeting the four sites are needed to fully activate PTEN phosphatase activity. Second, PI(4,5)P2 cannot activate the phosphopeptide phosphatase activity of PTEN, suggesting that PI(4,5)P2 can only activate the phospholipid phosphatase activity but not the phosphoprotein phosphatase activity of PTEN. Third, dephosphorylation of all four sites significantly decreases the affinity of PTEN for PI(4,5)P2. Since PI(4,5)P2 is a major phospholipid co-localizing with the phospholipid- and phosphoprotein-substrates in plasma membrane, we hypothesise that the reduced affinity facilitates PTEN to "hop" on the plasma membrane to dephosphorylate these substrates.
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Affiliation(s)
- Yeong-Chit Joel Chia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia; Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Bruno Catimel
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Daisy Sio Seng Lio
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia; Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ching-Seng Ang
- Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Benjamin Peng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Hong Wu
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia; Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Hong-Jian Zhu
- Department of Surgery, University of Melbourne, Royal Melbourne Hospital, Parkville, Victoria 3052, Australia
| | - Heung-Chin Cheng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia; Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia.
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50
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Nguyen HN, Yang JM, Miyamoto T, Itoh K, Rho E, Zhang Q, Inoue T, Devreotes PN, Sesaki H, Iijima M. Opening the conformation is a master switch for the dual localization and phosphatase activity of PTEN. Sci Rep 2015. [PMID: 26216063 PMCID: PMC4517176 DOI: 10.1038/srep12600] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Tumor suppressor PTEN mainly functions at two subcellular locations, the plasma membrane and the nucleus. At the plasma membrane, PTEN dephosphorylates the tumorigenic second messenger PIP3, which drives cell proliferation and migration. In the nucleus, PTEN controls DNA repair and genome stability independently of PIP3. Whereas the concept that a conformational change regulates protein function through post-translational modifications has been well established in biology, it is unknown whether a conformational change simultaneously controls dual subcellular localizations of proteins. Here, we discovered that opening the conformation of PTEN is the crucial upstream event that determines its key dual localizations of this crucial tumor suppressor. We identify a critical conformational switch that regulates PTEN's localization. Most PTEN molecules are held in the cytosol in a closed conformation by intramolecular interactions between the C-terminal tail and core region. Dephosphorylation of the tail opens the conformation and exposes the membrane-binding regulatory interface in the core region, recruiting PTEN to the membrane. Moreover, a lysine at residue 13 is also exposed and when ubiquitinated, transports PTEN to the nucleus. Thus, opening the conformation of PTEN is a key mechanism that enhances its dual localization and enzymatic activity, providing a potential therapeutic strategy in cancer treatments.
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Affiliation(s)
- Hoai-Nghia Nguyen
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Jr-Ming Yang
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Takafumi Miyamoto
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Kie Itoh
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Elmer Rho
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Qiang Zhang
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Takanari Inoue
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Peter N Devreotes
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Hiromi Sesaki
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Miho Iijima
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD
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