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Paratore TA, Schmidt GE, Ross AH, Gericke A. Thermal Stability of bivalent cation/phosphoinositide domains in model membranes. Chem Phys Lipids 2024:105424. [PMID: 39098579 DOI: 10.1016/j.chemphyslip.2024.105424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/06/2024]
Abstract
As key mediators in a wide array of signaling events, phosphoinositides (PIPs) orchestrate the recruitment of proteins to specific cellular locations at precise moments. This intricate spatiotemporal regulation of protein activity often necessitates the localized enrichment of the corresponding PIP. We investigate the extent and thermal stabilities of phosphatidylinositol-4-phosphate (PI(4)P), phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2 and phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) clusters with calcium and magnesium ions. We observe negligible or minimal clustering of all examined PIPs in the presence of Mg2+ ions. While PI(4)P shows in the presence of Ca2+ no clustering, PI(4,5)P2 forms with Ca2+ strong clusters that exhibit stablity up to at least 80°C. The extent of cluster formation for the interaction of PI(3,4,5)P3 with Ca2+ is less than what was observed for PI(4,5)P2, yet we still observe some clustering up to 80°C. Given that cholesterol has been demonstrated to enhance PIP clustering, we examined whether bivalent cations and cholesterol synergistically promote PIP clustering. We found that the interaction of Mg2+ or Ca2+ with PI(4)P remains extraordinarily weak, even in the presence of cholesterol. In contrast, we observe synergistic interaction of cholesterol and Ca2+ with PI(4,5)P2. Also, in the presence of cholesterol, the interaction of Mg2+ with PI(4,5)P2 remains weak. PI(3,4,5)P3 does not show strong clustering with cholesterol for the experimental conditions of our study and the interaction with Ca2+ and Mg2+ was not influenced by the presence of cholesterol.
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Affiliation(s)
- Trevor A Paratore
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA
| | - Greta E Schmidt
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA
| | - Alonzo H Ross
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA
| | - Arne Gericke
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA.
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Liang X, Jung SY, Fong LW, Bildik G, Gray JP, Mao W, Zhang S, Millward SW, Gorfe AA, Zhou Y, Lu Z, Bast RC. Membrane anchoring of the DIRAS3 N-terminal extension permits tumor suppressor function. iScience 2023; 26:108151. [PMID: 37915607 PMCID: PMC10616557 DOI: 10.1016/j.isci.2023.108151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 08/16/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023] Open
Abstract
DIRAS3 is an imprinted tumor suppressor gene encoding a GTPase that has a distinctive N-terminal extension (NTE) not found in other RAS proteins. This NTE and the prenylated C-terminus are required for DIRAS3-mediated inhibition of RAS/MAP signaling and PI3K activity at the plasma membrane. In this study, we applied biochemical, biophysical, and computational methods to characterize the structure and function of the NTE. The NTE peptide recognizes phosphoinositides PI(3,4,5)P3 and PI(4,5)P2 with rapid kinetics and strong affinity. Lipid binding induces NTE structural change from disorder to amphipathic helix. Mass spectrometry identified N-myristoylation of DIRAS3. All-atom molecular dynamic simulations predict DIRAS3 could adhere to the membrane through both termini, suggesting the NTE is involved in targeting and stabilizing DIRAS3 on the membrane by double anchoring. Overall, our results are consistent with DIRAS3's function as a tumor suppressor, whereby the membrane-bound DIRAS3 can effectively target PI3K and KRAS at the membrane.
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Affiliation(s)
- Xiaowen Liang
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Sung Yun Jung
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lon Wolf Fong
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Gamze Bildik
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Joshua P. Gray
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Weiqun Mao
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Shuxing Zhang
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Steven W. Millward
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Alemayehu A. Gorfe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhen Lu
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Robert C. Bast
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
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Krantz M, Eklund D, Särndahl E, Hedbrant A. A detailed molecular network map and model of the NLRP3 inflammasome. Front Immunol 2023; 14:1233680. [PMID: 38077364 PMCID: PMC10699087 DOI: 10.3389/fimmu.2023.1233680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/16/2023] [Indexed: 12/18/2023] Open
Abstract
The NLRP3 inflammasome is a key regulator of inflammation that responds to a broad range of stimuli. The exact mechanism of activation has not been determined, but there is a consensus on cellular potassium efflux as a major common denominator. Once NLRP3 is activated, it forms high-order complexes together with NEK7 that trigger aggregation of ASC into specks. Typically, there is only one speck per cell, consistent with the proposal that specks form - or end up at - the centrosome. ASC polymerisation in turn triggers caspase-1 activation, leading to maturation and release of IL-1β and pyroptosis, i.e., highly inflammatory cell death. Several gain-of-function mutations in the NLRP3 inflammasome have been suggested to induce spontaneous activation of NLRP3 and hence contribute to development and disease severity in numerous autoinflammatory and autoimmune diseases. Consequently, the NLRP3 inflammasome is of significant clinical interest, and recent attention has drastically improved our insight in the range of involved triggers and mechanisms of signal transduction. However, despite recent progress in knowledge, a clear and comprehensive overview of how these mechanisms interplay to shape the system level function is missing from the literature. Here, we provide such an overview as a resource to researchers working in or entering the field, as well as a computational model that allows for evaluating and explaining the function of the NLRP3 inflammasome system from the current molecular knowledge. We present a detailed reconstruction of the molecular network surrounding the NLRP3 inflammasome, which account for each specific reaction and the known regulatory constraints on each event as well as the mechanisms of drug action and impact of genetics when known. Furthermore, an executable model from this network reconstruction is generated with the aim to be used to explain NLRP3 activation from priming and activation to the maturation and release of IL-1β and IL-18. Finally, we test this detailed mechanistic model against data on the effect of different modes of inhibition of NLRP3 assembly. While the exact mechanisms of NLRP3 activation remains elusive, the literature indicates that the different stimuli converge on a single activation mechanism that is additionally controlled by distinct (positive or negative) priming and licensing events through covalent modifications of the NLRP3 molecule. Taken together, we present a compilation of the literature knowledge on the molecular mechanisms on NLRP3 activation, a detailed mechanistic model of NLRP3 activation, and explore the convergence of diverse NLRP3 activation stimuli into a single input mechanism.
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Affiliation(s)
- Marcus Krantz
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
| | - Daniel Eklund
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
| | - Eva Särndahl
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
| | - Alexander Hedbrant
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Örebro University, Örebro, Sweden
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4
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Nadel G, Maik-Rachline G, Seger R. JNK Cascade-Induced Apoptosis-A Unique Role in GqPCR Signaling. Int J Mol Sci 2023; 24:13527. [PMID: 37686335 PMCID: PMC10487481 DOI: 10.3390/ijms241713527] [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: 07/27/2023] [Revised: 08/27/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
The response of cells to extracellular signals is mediated by a variety of intracellular signaling pathways that determine stimulus-dependent cell fates. One such pathway is the cJun-N-terminal Kinase (JNK) cascade, which is mainly involved in stress-related processes. The cascade transmits its signals via a sequential activation of protein kinases, organized into three to five tiers. Proper regulation is essential for securing a proper cell fate after stimulation, and the mechanisms that regulate this cascade may involve the following: (1) Activatory or inhibitory phosphorylations, which induce or abolish signal transmission. (2) Regulatory dephosphorylation by various phosphatases. (3) Scaffold proteins that bring distinct components of the cascade in close proximity to each other. (4) Dynamic change of subcellular localization of the cascade's components. (5) Degradation of some of the components. In this review, we cover these regulatory mechanisms and emphasize the mechanism by which the JNK cascade transmits apoptotic signals. We also describe the newly discovered PP2A switch, which is an important mechanism for JNK activation that induces apoptosis downstream of the Gq protein coupled receptors. Since the JNK cascade is involved in many cellular processes that determine cell fate, addressing its regulatory mechanisms might reveal new ways to treat JNK-dependent pathologies.
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Affiliation(s)
| | | | - Rony Seger
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel; (G.N.); (G.M.-R.)
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Zhou W, Li W, Wang S, Salovska B, Hu Z, Tao B, Di Y, Punyamurtula U, Turk BE, Sessa WC, Liu Y. An optogenetic-phosphoproteomic study reveals dynamic Akt1 signaling profiles in endothelial cells. Nat Commun 2023; 14:3803. [PMID: 37365174 PMCID: PMC10293293 DOI: 10.1038/s41467-023-39514-1] [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: 07/08/2022] [Accepted: 06/07/2023] [Indexed: 06/28/2023] Open
Abstract
The serine/threonine kinase AKT is a central node in cell signaling. While aberrant AKT activation underlies the development of a variety of human diseases, how different patterns of AKT-dependent phosphorylation dictate downstream signaling and phenotypic outcomes remains largely enigmatic. Herein, we perform a systems-level analysis that integrates methodological advances in optogenetics, mass spectrometry-based phosphoproteomics, and bioinformatics to elucidate how different intensity, duration, and pattern of Akt1 stimulation lead to distinct temporal phosphorylation profiles in vascular endothelial cells. Through the analysis of ~35,000 phosphorylation sites across multiple conditions precisely controlled by light stimulation, we identify a series of signaling circuits activated downstream of Akt1 and interrogate how Akt1 signaling integrates with growth factor signaling in endothelial cells. Furthermore, our results categorize kinase substrates that are preferably activated by oscillating, transient, and sustained Akt1 signals. We validate a list of phosphorylation sites that covaried with Akt1 phosphorylation across experimental conditions as potential Akt1 substrates. Our resulting dataset provides a rich resource for future studies on AKT signaling and dynamics.
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Affiliation(s)
- Wenping Zhou
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06511, USA
- Vascular Biology & Therapeutics Program, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Wenxue Li
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA
- Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
| | - Shisheng Wang
- Department of Pulmonary and Critical Care Medicine, and Proteomics-Metabolomics Analysis Platform, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Barbora Salovska
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA
- Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
| | - Zhenyi Hu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA
- Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
| | - Bo Tao
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA
- Vascular Biology & Therapeutics Program, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Yi Di
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA
- Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
| | - Ujwal Punyamurtula
- Master of Biotechnology ScM Program, Brown University, Providence, RI, 02912, USA
| | - Benjamin E Turk
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - William C Sessa
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA.
- Vascular Biology & Therapeutics Program, Yale University School of Medicine, New Haven, CT, 06520, USA.
| | - Yansheng Liu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06510, USA.
- Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA.
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Shaw AL, Parson MAH, Truebestein L, Jenkins ML, Leonard TA, Burke JE. ATP-competitive and allosteric inhibitors induce differential conformational changes at the autoinhibitory interface of Akt1. Structure 2023; 31:343-354.e3. [PMID: 36758543 DOI: 10.1016/j.str.2023.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/21/2022] [Accepted: 01/13/2023] [Indexed: 02/11/2023]
Abstract
Akt is a master regulator of pro-growth signaling in the cell. Akt is activated by phosphoinositides that disrupt the autoinhibitory interface between the kinase and pleckstrin homology (PH) domains and then is phosphorylated at T308 and S473. Akt hyperactivation is oncogenic, which has spurred development of potent and selective inhibitors as therapeutics. Using hydrogen deuterium exchange mass spectrometry (HDX-MS), we interrogated the conformational changes upon binding Akt ATP-competitive and allosteric inhibitors. We compared inhibitors against three different states of Akt1. The allosteric inhibitor caused substantive conformational changes and restricts membrane binding. ATP-competitive inhibitors caused extensive allosteric conformational changes, altering the autoinhibitory interface and leading to increased membrane binding, suggesting that the PH domain is more accessible for membrane binding. This work provides unique insight into the autoinhibitory conformation of the PH and kinase domain and conformational changes induced by Akt inhibitors and has important implications for the design of Akt targeted therapeutics.
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Affiliation(s)
- Alexandria L Shaw
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada; Department of Biochemistry and Molecular Biology, the University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Matthew A H Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Linda Truebestein
- Department of Structural and Computational Biology, Max Perutz Labs, Campus Vienna Biocenter 5, 1030 Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Campus Vienna Biocenter 5, 1030 Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada; Department of Biochemistry and Molecular Biology, the University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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7
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Shim MS, Liton PB. The physiological and pathophysiological roles of the autophagy lysosomal system in the conventional aqueous humor outflow pathway: More than cellular clean up. Prog Retin Eye Res 2022; 90:101064. [PMID: 35370083 PMCID: PMC9464695 DOI: 10.1016/j.preteyeres.2022.101064] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/09/2022] [Accepted: 03/25/2022] [Indexed: 10/18/2022]
Abstract
During the last few years, the autophagy lysosomal system is emerging as a central cellular pathway with roles in survival, acting as a housekeeper and stress response mechanism. Studies by our and other labs suggest that autophagy might play an essential role in maintaining aqueous humor outflow homeostasis, and that malfunction of autophagy in outflow pathway cells might predispose to ocular hypertension and glaucoma pathogenesis. In this review, we will collect the current knowledge and discuss the molecular mechanisms by which autophagy does or might regulate normal outflow pathway tissue function, and its response to different types of stressors (oxidative stress and mechanical stress). We will also discuss novel roles of autophagy and lysosomal enzymes in modulation of TGFβ signaling and ECM remodeling, and the link between dysregulated autophagy and cellular senescence. We will examine what we have learnt, using pre-clinical animal models about how dysregulated autophagy can contribute to disease and apply that to the current status of autophagy in human glaucoma. Finally, we will consider and discuss the challenges and the potential of autophagy as a therapeutic target for the treatment of ocular hypertension and glaucoma.
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Affiliation(s)
- Myoung Sup Shim
- Duke University, Department of Ophthalmology, Durham, NC, 27705, USA
| | - Paloma B Liton
- Duke University, Department of Ophthalmology, Durham, NC, 27705, USA.
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8
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Circular dorsal ruffles disturb the growth factor-induced PI3K-AKT pathway in hepatocellular carcinoma Hep3B cells. Cell Commun Signal 2022; 20:102. [PMID: 35799301 PMCID: PMC9264614 DOI: 10.1186/s12964-022-00911-6] [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: 03/23/2022] [Accepted: 06/05/2022] [Indexed: 11/10/2022] Open
Abstract
Background Circular dorsal ruffles (CDRs) are rounded membrane ruffles induced on the dorsal surfaces of cells stimulated by growth factors (GF). They can serve as signal platforms to activate AKT protein kinase. After GF stimulation, phosphatidylinositol 3-kinase (PI3K) generates phosphatidylinositol (3,4,5)-triphosphate (PIP3) in the plasma membrane. PIP3 accumulates inside CDRs, recruits AKT into the structures, and phosphorylates them (pAKT). Given the importance of the PI3K-AKT pathway in GF signaling, CDRs are likely involved in cell growth. Interestingly, some cancer cell lines express CDRs. We hypothesized that CDRs contribute to carcinogenesis by modulating the AKT pathway. In the present study, we identified CDR-expressing cancer cell lines and investigated their cellular functions. Methods CDR formation was examined in six cancer cell lines in response to epidermal growth factor (EGF) and insulin. The morphology of the CDRs was characterized, and the related signaling molecules were observed using confocal and scanning electron microscopy. The role of CDRs in the AKT pathway was studied using biochemical analysis. The actin inhibitor cytochalasin D (Cyto D) and the PI3K inhibitor TGX221 were used to block CDRs. Results GF treatment induced CDRs in the hepatocellular carcinoma (HCC) Hep3B cell line, but not in others, including HCC cell lines HepG2 and Huh7, and the LO2 hepatocyte cell line. Confocal microscopy and western blot analysis showed that the PI3K-PIP3-AKT pathway was activated at the CDRs and that receptor proteins were recruited to the structures. Cyto D and TGX221 completely blocked CDRs and partially attenuated GF-induced pAKT. These results indicate that CDRs regulate the receptor-mediated PI3K-AKT pathway in Hep3B cells and the existence of CDR-independent pAKT mechanisms. Conclusions Our results showed that CDRs modulate the AKT pathway in Hep3B cells. Since CDRs were not observed in other HCC and hepatocyte cell lines, we propose that CDRs in Hep3B would determine the carcinoma characteristic of the cell by aberrantly triggering the AKT pathway. Signaling molecules involved in CDR formation are promising therapeutic targets for some types of HCC. Video abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-022-00911-6.
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Endocytic trafficking of GAS6-AXL complexes is associated with sustained AKT activation. Cell Mol Life Sci 2022; 79:316. [PMID: 35622156 PMCID: PMC9135597 DOI: 10.1007/s00018-022-04312-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 03/27/2022] [Accepted: 04/15/2022] [Indexed: 11/18/2022]
Abstract
AXL, a TAM receptor tyrosine kinase (RTK), and its ligand growth arrest-specific 6 (GAS6) are implicated in cancer metastasis and drug resistance, and cellular entry of viruses. Given this, AXL is an attractive therapeutic target, and its inhibitors are being tested in cancer and COVID-19 clinical trials. Still, astonishingly little is known about intracellular mechanisms that control its function. Here, we characterized endocytosis of AXL, a process known to regulate intracellular functions of RTKs. Consistent with the notion that AXL is a primary receptor for GAS6, its depletion was sufficient to block GAS6 internalization. We discovered that upon receptor ligation, GAS6–AXL complexes were rapidly internalized via several endocytic pathways including both clathrin-mediated and clathrin-independent routes, among the latter the CLIC/GEEC pathway and macropinocytosis. The internalization of AXL was strictly dependent on its kinase activity. In comparison to other RTKs, AXL was endocytosed faster and the majority of the internalized receptor was not degraded but rather recycled via SNX1-positive endosomes. This trafficking pattern coincided with sustained AKT activation upon GAS6 stimulation. Specifically, reduced internalization of GAS6–AXL upon the CLIC/GEEC downregulation intensified, whereas impaired recycling due to depletion of SNX1 and SNX2 attenuated AKT signaling. Altogether, our data uncover the coupling between AXL endocytic trafficking and AKT signaling upon GAS6 stimulation. Moreover, our study provides a rationale for pharmacological inhibition of AXL in antiviral therapy as viruses utilize GAS6–AXL-triggered endocytosis to enter cells.
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Sheetz JB, Lemmon MA, Tsutsui Y. Dynamics of protein kinases and pseudokinases by HDX-MS. Methods Enzymol 2022; 667:303-338. [PMID: 35525545 PMCID: PMC9148214 DOI: 10.1016/bs.mie.2022.03.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dynamics of the protein kinase fold are deeply intertwined with its structure. The past three decades of kinase biophysical studies revealed key dynamic features of the kinase domain and, more recently, how these features may endow catalytically impaired kinases-or pseudokinases-with signaling properties. Hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS) is proving to be a valuable approach for studies of kinase and pseudokinase domain dynamics. Here, we briefly discuss the methods that have provided insights into protein kinase dynamics, describe how HDX-MS is being used to answer questions in the kinase/pseudokinase field, and provide a detailed protocol for collecting an HDX-MS dataset to study the impacts of small molecule binding to a pseudokinase domain. As more small molecules are discovered that can disrupt pseudokinase conformations, HDX-MS is likely to be a powerful approach for exploring drug-induced changes in pseudokinase dynamics and structure.
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Affiliation(s)
- Joshua B Sheetz
- Department of Pharmacology and Yale Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, United States
| | - Mark A Lemmon
- Department of Pharmacology and Yale Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, United States.
| | - Yuko Tsutsui
- Department of Pharmacology and Yale Cancer Biology Institute, Yale University School of Medicine, West Haven, CT, United States.
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11
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Molecular Hydrogen Inhibits Colorectal Cancer Growth via the AKT/SCD1 Signaling Pathway. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8024452. [PMID: 35528164 PMCID: PMC9071919 DOI: 10.1155/2022/8024452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/09/2022] [Accepted: 04/12/2022] [Indexed: 12/24/2022]
Abstract
Objective Molecular hydrogen (H2) has been considered a potential therapeutic target in many cancers. Therefore, we sought to assess the potential effect of H2 on colorectal cancer (CRC) in this study. Methods The effect of H2 on the proliferation and apoptosis of RKO, SW480, and HCT116 CRC cell lines was assayed by CCK-8, colony formation, and flow cytometry assays. The effect of H2 on tumor growth was observed in xenograft implantation models (inhalation of 67% hydrogen two hours per day). Western blot and immunohistochemistry analyses were performed to examine the expression of p-PI3K, PI3K, AKT, pAKT, and SCD1 in CRC cell lines and xenograft mouse models. The expression of SCD1 in 491 formalin-fixed, paraffin-embedded CRC specimens was investigated with immunochemistry. The relationship between SCD1 status and clinicopathological characteristics and outcomes was determined. Results Hydrogen treatment suppressed the proliferation of CRC cell lines independent of apoptosis, and the cell lines showed different responses to different doses of H2. Hydrogen also elicited a potent antitumor effect to reduce CRC tumor volume and weight in vivo. Western blot and IHC staining demonstrated that H2 inhibits CRC cell proliferation by decreasing pAKT/SCD1 levels, and the inhibition of cell proliferation induced by H2 was reversed by the AKT activator SC79. IHC showed that SCD1 expression was significantly higher in CRC tissues than in normal epithelial tissues (70.3% vs. 29.7%, p = 0.02) and was correlated with a more advanced TNM stage (III vs. I + II; 75.9% vs. 66.3%, p = 0.02), lymph node metastasis (with vs. without; 75.9% vs. 66.3%, p = 0.02), and patients without a family history of CRC (78.7% vs. 62.1%, p = 0.047). Conclusion This study demonstrates that high concentrations of H2 exert an inhibitory effect on CRC by inhibiting the pAKT/SCD1 pathway. Further studies are warranted for clinical evaluation of H2 as SCD1 inhibitor to target CRC.
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12
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Nussinov R, Zhang M, Maloney R, Tsai CJ, Yavuz BR, Tuncbag N, Jang H. Mechanism of activation and the rewired network: New drug design concepts. Med Res Rev 2021; 42:770-799. [PMID: 34693559 PMCID: PMC8837674 DOI: 10.1002/med.21863] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/06/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Precision oncology benefits from effective early phase drug discovery decisions. Recently, drugging inactive protein conformations has shown impressive successes, raising the cardinal questions of which targets can profit and what are the principles of the active/inactive protein pharmacology. Cancer driver mutations have been established to mimic the protein activation mechanism. We suggest that the decision whether to target an inactive (or active) conformation should largely rest on the protein mechanism of activation. We next discuss the recent identification of double (multiple) same-allele driver mutations and their impact on cell proliferation and suggest that like single driver mutations, double drivers also mimic the mechanism of activation. We further suggest that the structural perturbations of double (multiple) in cis mutations may reveal new surfaces/pockets for drug design. Finally, we underscore the preeminent role of the cellular network which is deregulated in cancer. Our structure-based review and outlook updates the traditional Mechanism of Action, informs decisions, and calls attention to the intrinsic activation mechanism of the target protein and the rewired tumor-specific network, ushering innovative considerations in precision medicine.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
| | - Ryan Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
| | - Bengi Ruken Yavuz
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey
| | - Nurcan Tuncbag
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey.,Department of Chemical and Biological Engineering, College of Engineering, Koc University, Istanbul, Turkey.,Koc University Research Center for Translational Medicine, School of Medicine, Koc University, Istanbul, Turkey
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
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13
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Primary cilia and the reciprocal activation of AKT and SMAD2/3 regulate stretch-induced autophagy in trabecular meshwork cells. Proc Natl Acad Sci U S A 2021; 118:2021942118. [PMID: 33753495 DOI: 10.1073/pnas.2021942118] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Activation of autophagy is one of the responses elicited by high intraocular pressure (IOP) and mechanical stretch in trabecular meshwork (TM) cells. However, the mechanosensor and the molecular mechanisms by which autophagy is induced by mechanical stretch in these or other cell types is largely unknown. Here, we have investigated the mechanosensor and downstream signaling pathway that regulate cyclic mechanical stretch (CMS)-induced autophagy in TM cells. We report that primary cilia act as a mechanosensor for CMS-induced autophagy and identified a cross-regulatory talk between AKT1 and noncanonical SMAD2/3 signaling as critical components of primary cilia-mediated activation of autophagy by mechanical stretch. Furthermore, we demonstrated the physiological significance of our findings in ex vivo perfused eyes. Removal of primary cilia disrupted the homeostatic IOP compensatory response and prevented the increase in LC3-II protein levels in response to elevated pressure challenge, strongly supporting a role of primary cilia-mediated autophagy in regulating IOP homeostasis.
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14
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Truebestein L, Hornegger H, Anrather D, Hartl M, Fleming KD, Stariha JTB, Pardon E, Steyaert J, Burke JE, Leonard TA. Structure of autoinhibited Akt1 reveals mechanism of PIP 3-mediated activation. Proc Natl Acad Sci U S A 2021; 118:e2101496118. [PMID: 34385319 PMCID: PMC8379990 DOI: 10.1073/pnas.2101496118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The protein kinase Akt is one of the primary effectors of growth factor signaling in the cell. Akt responds specifically to the lipid second messengers phosphatidylinositol-3,4,5-trisphosphate [PI(3,4,5)P3] and phosphatidylinositol-3,4-bisphosphate [PI(3,4)P2] via its PH domain, leading to phosphorylation of its activation loop and the hydrophobic motif of its kinase domain, which are critical for activity. We have now determined the crystal structure of Akt1, revealing an autoinhibitory interface between the PH and kinase domains that is often mutated in cancer and overgrowth disorders. This interface persists even after stoichiometric phosphorylation, thereby restricting maximum Akt activity to PI(3,4,5)P3- or PI(3,4)P2-containing membranes. Our work helps to resolve the roles of lipids and phosphorylation in the activation of Akt and has wide implications for the spatiotemporal control of Akt and potentially lipid-activated kinase signaling in general.
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Affiliation(s)
- Linda Truebestein
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Harald Hornegger
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Dorothea Anrather
- Mass Spectrometry Core Facility, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
| | - Markus Hartl
- Mass Spectrometry Core Facility, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jordan T B Stariha
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), 1050 Brussels, Belgium
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), 1050 Brussels, Belgium
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria;
- Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
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15
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Rascio F, Spadaccino F, Rocchetti MT, Castellano G, Stallone G, Netti GS, Ranieri E. The Pathogenic Role of PI3K/AKT Pathway in Cancer Onset and Drug Resistance: An Updated Review. Cancers (Basel) 2021; 13:3949. [PMID: 34439105 PMCID: PMC8394096 DOI: 10.3390/cancers13163949] [Citation(s) in RCA: 141] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
The PI3K/AKT pathway is one of the most frequently over-activated intracellular pathways in several human cancers. This pathway, acting on different downstream target proteins, contributes to the carcinogenesis, proliferation, invasion, and metastasis of tumour cells. A multi-level impairment, involving mutation and genetic alteration, aberrant regulation of miRNAs sequences, and abnormal phosphorylation of cascade factors, has been found in multiple cancer types. The deregulation of this pathway counteracts common therapeutic strategies and contributes to multidrug resistance. In this review, we underline the involvement of this pathway in patho-physiological cell survival mechanisms, emphasizing its key role in the development of drug resistance. We also provide an overview of the potential inhibition strategies currently available.
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Affiliation(s)
- Federica Rascio
- Nephrology Dialysis and Transplantation Unit, Advanced Research Center on Kidney Aging (A.R.K.A.), Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (G.C.); (G.S.)
| | - Federica Spadaccino
- Clinical Pathology Unit, Advanced Research Center on Kidney Aging (A.R.K.A.), Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (F.S.); (G.S.N.); (E.R.)
| | - Maria Teresa Rocchetti
- Cell Biology Unit, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
| | - Giuseppe Castellano
- Nephrology Dialysis and Transplantation Unit, Advanced Research Center on Kidney Aging (A.R.K.A.), Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (G.C.); (G.S.)
| | - Giovanni Stallone
- Nephrology Dialysis and Transplantation Unit, Advanced Research Center on Kidney Aging (A.R.K.A.), Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (G.C.); (G.S.)
| | - Giuseppe Stefano Netti
- Clinical Pathology Unit, Advanced Research Center on Kidney Aging (A.R.K.A.), Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (F.S.); (G.S.N.); (E.R.)
| | - Elena Ranieri
- Clinical Pathology Unit, Advanced Research Center on Kidney Aging (A.R.K.A.), Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (F.S.); (G.S.N.); (E.R.)
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16
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Pokorny D, Truebestein L, Fleming KD, Burke JE, Leonard TA. In vitro reconstitution of Sgk3 activation by phosphatidylinositol 3-phosphate. J Biol Chem 2021; 297:100919. [PMID: 34181950 PMCID: PMC8318898 DOI: 10.1016/j.jbc.2021.100919] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/09/2021] [Accepted: 06/23/2021] [Indexed: 12/19/2022] Open
Abstract
Serum- and glucocorticoid-regulated kinase 3 (Sgk3) is a serine/threonine protein kinase activated by the phospholipid phosphatidylinositol 3-phosphate (PI3P) downstream of growth factor signaling via class I phosphatidylinositol 3-kinase (PI3K) signaling and by class III PI3K/Vps34-mediated PI3P production on endosomes. Upregulation of Sgk3 activity has recently been linked to a number of human cancers; however, the precise mechanism of activation of Sgk3 is unknown. Here, we use a wide range of cell biological, biochemical, and biophysical techniques, including hydrogen-deuterium exchange mass spectrometry, to investigate the mechanism of activation of Sgk3 by PI3P. We show that Sgk3 is regulated by a combination of phosphorylation and allosteric activation. We demonstrate that binding of Sgk3 to PI3P via its regulatory phox homology (PX) domain induces large conformational changes in Sgk3 associated with its activation and that the PI3P-binding pocket of the PX domain of Sgk3 is sequestered in its inactive conformation. Finally, we reconstitute Sgk3 activation via Vps34-mediated PI3P synthesis on phosphatidylinositol liposomes in vitro. In addition to identifying the mechanism of Sgk3 activation by PI3P, our findings open up potential therapeutic avenues in allosteric inhibitor development to target Sgk3 in cancer.
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Affiliation(s)
- Daniel Pokorny
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Linda Truebestein
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria.
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17
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Guerra B, Recio C, Aranda-Tavío H, Guerra-Rodríguez M, García-Castellano JM, Fernández-Pérez L. The Mevalonate Pathway, a Metabolic Target in Cancer Therapy. Front Oncol 2021; 11:626971. [PMID: 33718197 PMCID: PMC7947625 DOI: 10.3389/fonc.2021.626971] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 01/18/2021] [Indexed: 12/12/2022] Open
Abstract
A hallmark of cancer cells includes a metabolic reprograming that provides energy, the essential building blocks, and signaling required to maintain survival, rapid growth, metastasis, and drug resistance of many cancers. The influence of tumor microenviroment on cancer cells also results an essential driving force for cancer progression and drug resistance. Lipid-related enzymes, lipid-derived metabolites and/or signaling pathways linked to critical regulators of lipid metabolism can influence gene expression and chromatin remodeling, cellular differentiation, stress response pathways, or tumor microenviroment, and, collectively, drive tumor development. Reprograming of lipid metabolism includes a deregulated activity of mevalonate (MVA)/cholesterol biosynthetic pathway in specific cancer cells which, in comparison with normal cell counterparts, are dependent of the continuous availability of MVA/cholesterol-derived metabolites (i.e., sterols and non-sterol intermediates) for tumor development. Accordingly, there are increasing amount of data, from preclinical and epidemiological studies, that support an inverse association between the use of statins, potent inhibitors of MVA biosynthetic pathway, and mortality rate in specific cancers (e.g., colon, prostate, liver, breast, hematological malignances). In contrast, despite the tolerance and therapeutic efficacy shown by statins in cardiovascular disease, cancer treatment demands the use of relatively high doses of single statins for a prolonged period, thereby limiting this therapeutic strategy due to adverse effects. Clinically relevant, synergistic effects of tolerable doses of statins with conventional chemotherapy might enhance efficacy with lower doses of each drug and, probably, reduce adverse effects and resistance. In spite of that, clinical trials to identify combinatory therapies that improve therapeutic window are still a challenge. In the present review, we revisit molecular evidences showing that deregulated activity of MVA biosynthetic pathway has an essential role in oncogenesis and drug resistance, and the potential use of MVA pathway inhibitors to improve therapeutic window in cancer.
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Affiliation(s)
- Borja Guerra
- Molecular and Translational Pharmacology Lab, Institute for Biomedical and Health Research (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Carlota Recio
- Molecular and Translational Pharmacology Lab, Institute for Biomedical and Health Research (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Haidée Aranda-Tavío
- Molecular and Translational Pharmacology Lab, Institute for Biomedical and Health Research (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Miguel Guerra-Rodríguez
- Molecular and Translational Pharmacology Lab, Institute for Biomedical and Health Research (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - José M García-Castellano
- Molecular and Translational Pharmacology Lab, Institute for Biomedical and Health Research (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Leandro Fernández-Pérez
- Molecular and Translational Pharmacology Lab, Institute for Biomedical and Health Research (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
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18
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Blaustein M, Piegari E, Martínez Calejman C, Vila A, Amante A, Manese MV, Zeida A, Abrami L, Veggetti M, Guertin DA, van der Goot FG, Corvi MM, Colman-Lerner A. Akt Is S-Palmitoylated: A New Layer of Regulation for Akt. Front Cell Dev Biol 2021; 9:626404. [PMID: 33659252 PMCID: PMC7917195 DOI: 10.3389/fcell.2021.626404] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/25/2021] [Indexed: 11/13/2022] Open
Abstract
The protein kinase Akt/PKB participates in a great variety of processes, including translation, cell proliferation and survival, as well as malignant transformation and viral infection. In the last few years, novel Akt posttranslational modifications have been found. However, how these modification patterns affect Akt subcellular localization, target specificity and, in general, function is not thoroughly understood. Here, we postulate and experimentally demonstrate by acyl-biotin exchange (ABE) assay and 3H-palmitate metabolic labeling that Akt is S-palmitoylated, a modification related to protein sorting throughout subcellular membranes. Mutating cysteine 344 into serine blocked Akt S-palmitoylation and diminished its phosphorylation at two key sites, T308 and T450. Particularly, we show that palmitoylation-deficient Akt increases its recruitment to cytoplasmic structures that colocalize with lysosomes, a process stimulated during autophagy. Finally, we found that cysteine 344 in Akt1 is important for proper its function, since Akt1-C344S was unable to support adipocyte cell differentiation in vitro. These results add an unexpected new layer to the already complex Akt molecular code, improving our understanding of cell decision-making mechanisms such as cell survival, differentiation and death.
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Affiliation(s)
- Matías Blaustein
- Departamento de Fisiología, Biología Molecular y Celular (DFBMC), Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.,Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA, Buenos Aires, Argentina.,Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Estefanía Piegari
- Departamento de Fisiología, Biología Molecular y Celular (DFBMC), Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.,Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA, Buenos Aires, Argentina
| | - Camila Martínez Calejman
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Antonella Vila
- Departamento de Fisiología, Biología Molecular y Celular (DFBMC), Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.,Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA, Buenos Aires, Argentina.,Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Analía Amante
- Departamento de Fisiología, Biología Molecular y Celular (DFBMC), Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.,Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA, Buenos Aires, Argentina.,Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Victoria Manese
- Laboratorio de bioquímica y biología celular de parásitos, Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM) - CONICET, Chascomús, Argentina
| | - Ari Zeida
- Departamento de Bioquímica and Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Laurence Abrami
- Global Health Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Mariela Veggetti
- Departamento de Fisiología, Biología Molecular y Celular (DFBMC), Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.,Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA, Buenos Aires, Argentina
| | - David A Guertin
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States.,Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, United States.,Lei Weibo Institute for Rare Diseases, University of Massachusetts Medical School, Worcester, MA, United States
| | - F Gisou van der Goot
- Global Health Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - María Martha Corvi
- Laboratorio de bioquímica y biología celular de parásitos, Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM) - CONICET, Chascomús, Argentina
| | - Alejandro Colman-Lerner
- Departamento de Fisiología, Biología Molecular y Celular (DFBMC), Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.,Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-UBA, Buenos Aires, Argentina
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19
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Dai X, Zhang Y, Lin X, Huang X, Zhang Y, Xue C, Chen W, Ye J, Lin X, Lin X. SIK2 represses AKT/GSK3β/β-catenin signaling and suppresses gastric cancer by inhibiting autophagic degradation of protein phosphatases. Mol Oncol 2021; 15:228-245. [PMID: 33128264 PMCID: PMC7782074 DOI: 10.1002/1878-0261.12838] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 08/20/2020] [Accepted: 10/28/2020] [Indexed: 12/24/2022] Open
Abstract
Salt-inducible kinase 2 (SIK2) is an important regulator in various intracellular signaling pathways related to apoptosis, tumorigenesis and metastasis. However, the involvement of SIK2 in gastric tumorigenesis and the functional linkage with gastric cancer (GC) progression remain to be defined. Here, we report that SIK2 was significantly downregulated in human GC tissues, and reduced SIK2 expression was associated with poor prognosis of patients. Overexpression of SIK2 suppressed the migration and invasion of GC cells, whereas knockdown of SIK2 enhanced cell migratory and invasive capability as well as metastatic potential. These changes in the malignant phenotype resulted from the ability of SIK2 to suppress epithelial-mesenchymal transition via inhibition of AKT/GSK3β/β-catenin signaling. The inhibitory effect of SIK2 on AKT/GSK3β/β-catenin signaling was mediated primarily through inactivation of AKT, due to its enhanced dephosphorylation by the upregulated protein phosphatases PHLPP2 and PP2A. The upregulation of PHLPP2 and PP2A was attributable to SIK2 phosphorylation and activation of mTORC1, which inhibited autophagic degradation of these two phosphatases. These results suggest that SIK2 acts as a tumor suppressor in GC and may serve as a novel prognostic biomarker and therapeutic target for this tumor.
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Affiliation(s)
- Xiao‐man Dai
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
- Fujian Key Laboratory of Tumor MicrobiologyFujian Medical UniversityFuzhouChina
| | - Yan‐hui Zhang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
| | - Xiao‐han Lin
- Department of Gastrointestinal SurgeryThe First Affiliated Hospital of Fujian Medical UniversityFuzhouChina
| | - Xiao‐xing Huang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
| | - Yi Zhang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
| | - Chao‐rong Xue
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
| | - Wan‐nan Chen
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
| | - Jian‐xin Ye
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
- Department of Gastrointestinal SurgeryThe First Affiliated Hospital of Fujian Medical UniversityFuzhouChina
| | - Xin‐jian Lin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
| | - Xu Lin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University)Ministry of EducationFuzhouChina
- Fujian Key Laboratory of Tumor MicrobiologyFujian Medical UniversityFuzhouChina
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20
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Plotz G, Lopez-Garcia LA, Brieger A, Zeuzem S, Biondi RM. Alternative AKT2 splicing produces protein lacking the hydrophobic motif regulatory region. PLoS One 2020; 15:e0242819. [PMID: 33253205 PMCID: PMC7703976 DOI: 10.1371/journal.pone.0242819] [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: 09/29/2020] [Accepted: 11/09/2020] [Indexed: 12/20/2022] Open
Abstract
Three AKT serine/threonine kinase isoforms (AKT1/AKT2/AKT3) mediate proliferation, metabolism, differentiation and anti-apoptotic signals. AKT isoforms are activated downstream of PI3-kinase and also by PI3-kinase independent mechanisms. Mutations in the lipid phosphatase PTEN and PI3-kinase that increase PIP3 levels increase AKT signaling in a large proportion of human cancers. AKT and other AGC kinases possess a regulatory mechanism that relies on a conserved hydrophobic motif (HM) C-terminal to the catalytic core. In AKT, the HM is contiguous to the serine 473 and two other newly discovered (serine 477 and tyrosine 479) regulatory phosphorylation sites. In AKT genes, this regulatory HM region is encoded in the final exon. We identified a splice variant of AKT2 (AKT2-13a), which contains an alternative final exon and lacks the HM regulatory site. We validated the presence of mRNA for this AKT2-13a splice variant in different tissues, and the presence of AKT2-13a protein in extracts from HEK293 cells. When overexpressed in HEK293 cells, AKT2-13a is phosphorylated at the activation loop and at the zipper/turn motif phosphorylation sites but has reduced specific activity. Analysis of the human transcriptome corresponding to other AGC kinases revealed that all three AKT isoforms express alternative transcripts lacking the HM regulatory motif, which was not the case for SGK1-3, S6K1-2, and classical, novel and atypical PKC isoforms. The transcripts of splice variants of Akt1-3 excluding the HM regulatory region could lead to expression of deregulated forms of AKT.
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Affiliation(s)
- Guido Plotz
- Biomedizinisches Forschungslabor, Medizinische Klinik 1, Universitätsklinik Frankfurt, Frankfurt, Germany
| | - Laura A Lopez-Garcia
- German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Angela Brieger
- Biomedizinisches Forschungslabor, Medizinische Klinik 1, Universitätsklinik Frankfurt, Frankfurt, Germany
| | - Stefan Zeuzem
- Biomedizinisches Forschungslabor, Medizinische Klinik 1, Universitätsklinik Frankfurt, Frankfurt, Germany
| | - Ricardo M Biondi
- Biomedizinisches Forschungslabor, Medizinische Klinik 1, Universitätsklinik Frankfurt, Frankfurt, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany.,Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society, Buenos Aires, Argentina
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21
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Maffucci T, Falasca M. Inositol Polyphosphate-Based Compounds as Inhibitors of Phosphoinositide 3-Kinase-Dependent Signaling. Int J Mol Sci 2020; 21:E7198. [PMID: 33003448 PMCID: PMC7582811 DOI: 10.3390/ijms21197198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
Signaling pathways regulated by the phosphoinositide 3-kinase (PI3K) enzymes have a well-established role in cancer development and progression. Over the past 30 years, the therapeutic potential of targeting this pathway has been well recognized, and this has led to the development of a multitude of drugs, some of which have progressed into clinical trials, with few of them currently approved for use in specific cancer settings. While many inhibitors compete with ATP, hence preventing the catalytic activity of the kinases directly, a deep understanding of the mechanisms of PI3K-dependent activation of its downstream effectors led to the development of additional strategies to prevent the initiation of this signaling pathway. This review summarizes previously published studies that led to the identification of inositol polyphosphates as promising parent molecules to design novel inhibitors of PI3K-dependent signals. We focus our attention on the inhibition of protein-membrane interactions mediated by binding of pleckstrin homology domains and phosphoinositides that we proposed 20 years ago as a novel therapeutic strategy.
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Affiliation(s)
- Tania Maffucci
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Marco Falasca
- Metabolic Signalling Group, School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, Australia
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Bohnert M. Tether Me, Tether Me Not—Dynamic Organelle Contact Sites in Metabolic Rewiring. Dev Cell 2020; 54:212-225. [DOI: 10.1016/j.devcel.2020.06.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/17/2020] [Accepted: 06/20/2020] [Indexed: 02/04/2023]
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