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Yamane T, Nakayama T, Ekimoto T, Inoue M, Ikezaki K, Sekiguchi H, Kuramochi M, Terao Y, Judai K, Saito M, Ikeguchi M, Sasaki YC. Comparison of the Molecular Motility of Tubulin Dimeric Isoforms: Molecular Dynamics Simulations and Diffracted X-ray Tracking Study. Int J Mol Sci 2023; 24:15423. [PMID: 37895101 PMCID: PMC10607685 DOI: 10.3390/ijms242015423] [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: 07/31/2023] [Revised: 10/11/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
Tubulin has been recently reported to form a large family consisting of various gene isoforms; however, the differences in the molecular features of tubulin dimers composed of a combination of these isoforms remain unknown. Therefore, we attempted to elucidate the physical differences in the molecular motility of these tubulin dimers using the method of measurable pico-meter-scale molecular motility, diffracted X-ray tracking (DXT) analysis, regarding characteristic tubulin dimers, including neuronal TUBB3 and ubiquitous TUBB5. We first conducted a DXT analysis of neuronal (TUBB3-TUBA1A) and ubiquitous (TUBB5-TUBA1B) tubulin dimers and found that the molecular motility around the vertical axis of the neuronal tubulin dimer was lower than that of the ubiquitous tubulin dimer. The results of molecular dynamics (MD) simulation suggest that the difference in motility between the neuronal and ubiquitous tubulin dimers was probably caused by a change in the major contact of Gln245 in the T7 loop of TUBB from Glu11 in TUBA to Val353 in TUBB. The present study is the first report of a novel phenomenon in which the pico-meter-scale molecular motility between neuronal and ubiquitous tubulin dimers is different.
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Affiliation(s)
- Tsutomu Yamane
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; (T.E.); (M.I.); (M.I.)
- HPC- and AI-Driven Drug Development Platform Division, Riken Center for Computational Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takahiro Nakayama
- Department of Medical Physiology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka 181-8611, Japan; (T.N.); (Y.T.)
| | - Toru Ekimoto
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; (T.E.); (M.I.); (M.I.)
| | - Masao Inoue
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; (T.E.); (M.I.); (M.I.)
| | - Keigo Ikezaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8568, Japan; (K.I.); (M.K.)
| | - Hiroshi Sekiguchi
- Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo 679-5198, Japan;
| | - Masahiro Kuramochi
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8568, Japan; (K.I.); (M.K.)
| | - Yasuo Terao
- Department of Medical Physiology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka 181-8611, Japan; (T.N.); (Y.T.)
| | - Ken Judai
- Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Tokyo 156-8550, Japan;
| | - Minoru Saito
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo 156-8550, Japan;
| | - Mitsunori Ikeguchi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; (T.E.); (M.I.); (M.I.)
- HPC- and AI-Driven Drug Development Platform Division, Riken Center for Computational Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Yuji C. Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8568, Japan; (K.I.); (M.K.)
- Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo 679-5198, Japan;
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
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Quercetin inhibits glucose transport by binding to an exofacial site on GLUT1. Biochimie 2018; 151:107-114. [PMID: 29857184 DOI: 10.1016/j.biochi.2018.05.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 05/25/2018] [Indexed: 12/27/2022]
Abstract
Quercetin, a common dietary flavone, is a competitive inhibitor of glucose uptake and is also thought to be transported into cells by GLUT1. In this study, we confirm that quercetin is a competitive inhibitor of GLUT1 and also demonstrate that newly synthesized compounds, WZB-117 and BAY-876 are robust inhibitors of GLUT1 in L929 cells. To measure quercetin interaction with L929 cells, we develop a new fluorescent assay using flow cytometry. The binding of quercetin and its inhibitory effects on 2-deoxyglucose (2DG) uptake showed nearly identical dose dependent effects, with both having maximum effects between 50 and 100 μM and similar half maximum effects at 8.9 and 8.5 μM respectively. The interaction of quercetin was rapid with t1/2 of 54 s and the onset and loss of its inhibitory effects on 2DG uptake were equally fast. This suggests that either quercetin is simply binding to surface GLUT1 or its transport in and out of the cell reaches equilibrium very quickly. If quercetin is transported, the co-incubation of quercetin with other glucose inhibitors should block quercetin uptake. However, we observed that WZB-117, an exofacial binding inhibitor of GLUT1 reduced quercetin interaction, while cytochalasin B, an endofacial binding inhibitor, enhanced quercetin interaction, and BAY-876 had no effect on quercetin interaction. Taken together, these data are more consistent with quercetin simply binding to GLUT1, but not actually being transported into L929 cells via the glucose channel in GLUT1.
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Giovannone AJ, Winterstein C, Bhattaram P, Reales E, Low SH, Baggs JE, Xu M, Lalli MA, Hogenesch JB, Weimbs T. Soluble syntaxin 3 functions as a transcriptional regulator. J Biol Chem 2018; 293:5478-5491. [PMID: 29475951 DOI: 10.1074/jbc.ra117.000874] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/20/2018] [Indexed: 01/06/2023] Open
Abstract
Syntaxins are a conserved family of SNARE proteins and contain C-terminal transmembrane anchors required for their membrane fusion activity. Here we show that Stx3 (syntaxin 3) unexpectedly also functions as a nuclear regulator of gene expression. We found that alternative splicing creates a soluble isoform that we termed Stx3S, lacking the transmembrane anchor. Soluble Stx3S binds to the nuclear import factor RanBP5 (RAN-binding protein 5), targets to the nucleus, and interacts physically and functionally with several transcription factors, including ETV4 (ETS variant 4) and ATF2 (activating transcription factor 2). Stx3S is differentially expressed in normal human tissues, during epithelial cell polarization, and in breast cancer versus normal breast tissue. Inhibition of endogenous Stx3S expression alters the expression of cancer-associated genes and promotes cell proliferation. Similar nuclear-targeted, soluble forms of other syntaxins were identified, suggesting that nuclear signaling is a conserved, novel function common among these membrane-trafficking proteins.
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Affiliation(s)
- Adrian J Giovannone
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Christine Winterstein
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Pallavi Bhattaram
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Elena Reales
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Seng Hui Low
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Julie E Baggs
- the Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Mimi Xu
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - Matthew A Lalli
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625
| | - John B Hogenesch
- the Center for Chronobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Thomas Weimbs
- From the Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9625,
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Abstract
The early/recycling endosomes of an eukaryotic cell perform diverse cellular functions. In addition, the endosomal system generates multiple organelles, including certain cell type-specific organelles called lysosome-related organelles (LROs). The biosynthesis of these organelles possibly occurs through a sequential maturation process in which the cargo-containing endosomal vesicular/tubular structures are fused with the maturing organelle. The molecular machinery that regulates the cargo delivery or the membrane fusion during LRO biogenesis is poorly understood. Here, we describe the known key molecules, such as SNAREs, that regulate both the biogenesis and secretion of multiple LROs. Moreover, we also describe other regulatory molecules, such as Rab GTPases and their effectors that modulate the SNARE activity for cargo delivery to one such LRO, the melanosome. Overall, this review will increase our current understanding of LRO biogenesis and function.
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Affiliation(s)
- Riddhi Atul Jani
- a Department of Microbiology and Cell Biology ; Indian Institute of Science ; Bangalore , India
| | - Sarmistha Mahanty
- a Department of Microbiology and Cell Biology ; Indian Institute of Science ; Bangalore , India
| | - Subba Rao Gangi Setty
- a Department of Microbiology and Cell Biology ; Indian Institute of Science ; Bangalore , India
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Kosiorek M, Podszywalow-Bartnicka P, Zylinska L, Pikula S. NFAT1 and NFAT3 cooperate with HDAC4 during regulation of alternative splicing of PMCA isoforms in PC12 cells. PLoS One 2014; 9:e99118. [PMID: 24905014 PMCID: PMC4048221 DOI: 10.1371/journal.pone.0099118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/10/2014] [Indexed: 02/07/2023] Open
Abstract
Background The bulk of human genes undergo alternative splicing (AS) upon response to physiological stimuli. AS is a great source of protein diversity and biological processes and is associated with the development of many diseases. Pheochromocytoma is a neuroendocrine tumor, characterized by an excessive Ca2+-dependent secretion of catecholamines. This underlines the importance of balanced control of calcium transport via regulation of gene expression pattern, including different calcium transport systems, such as plasma membrane Ca2+-ATPases (PMCAs), abundantly expressed in pheochromocytoma chromaffin cells (PC12 cells). PMCAs are encoded by four genes (Atp2b1, Atp2b2, Atp2b3, Atp2b4), whose transcript products undergo alternative splicing giving almost 30 variants. Results In this scientific report, we propose a novel mechanism of regulation of PMCA alternative splicing in PC12 cells through cooperation of the nuclear factor of activated T-cells (NFAT) and histone deacetylases (HDACs). Luciferase assays showed increased activity of NFAT in PC12 cells, which was associated with altered expression of PMCA. RT-PCR experiments suggested that inhibition of the transcriptional activity of NFAT might result in the rearrangement of PMCA splicing variants in PC12 cells. NFAT inhibition led to dominant expression of 2x/c, 3x/a and 4x/a PMCA variants, while in untreated cells the 2w,z/b, 3z,x/b,c,e,f, and 4x/b variants were found as well. Furthermore, chromatin immunoprecipitation experiments showed that NFAT1-HDAC4 or NFAT3-HDAC4 complexes might be involved in regulation of PMCA2x splicing variant generation. Conclusions We suggest that the influence of NFAT/HDAC on PMCA isoform composition might be important for altered dopamine secretion by PC12 cells.
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Affiliation(s)
- Michalina Kosiorek
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
- Department of Neurodegenerative Disorders, Laboratory of Neurogenetics, Mossakowski Medical Research Centre PAS, Warsaw, Poland
| | | | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, Lodz, Poland
| | - Slawomir Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
- * E-mail:
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Palmer CS, Ostrowski M, Gouillou M, Tsai L, Yu D, Zhou J, Henstridge DC, Maisa A, Hearps AC, Lewin SR, Landay A, Jaworowski A, McCune JM, Crowe SM. Increased glucose metabolic activity is associated with CD4+ T-cell activation and depletion during chronic HIV infection. AIDS 2014; 28:297-309. [PMID: 24335483 PMCID: PMC4293200 DOI: 10.1097/qad.0000000000000128] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVES Glucose metabolism plays a fundamental role in supporting the growth, proliferation and effector functions of T cells. We investigated the impact of HIV infection on key processes that regulate glucose uptake and metabolism in primary CD4 and CD8 T cells. DESIGN AND METHODS Thirty-eight HIV-infected treatment-naive, 35 HIV+/combination antiretroviral therapy, seven HIV+ long-term nonprogressors and 25 HIV control individuals were studied. Basal markers of glycolysis [e.g. glucose transporter-1 (Glut1) expression, glucose uptake, intracellular glucose-6-phosphate, and L-lactate] were measured in T cells. The cellular markers of immune activation, CD38 and HLA-DR, were measured by flow cytometry. RESULTS The surface expression of the Glut1 is up-regulated in CD4 T cells in HIV-infected patients compared with uninfected controls. The percentage of circulating CD4Glut1 T cells was significantly increased in HIV-infected patients and was not restored to normal levels following combination antiretroviral therapy. Basal markers of glycolysis were significantly higher in CD4Glut1 T cells compared to CD4Glut1 T cells. The proportion of CD4Glut1 T cells correlated positively with the expression of the cellular activation marker, HLA-DR, on total CD4 T cells, but inversely with the absolute CD4 T-cell count irrespective of HIV treatment status. CONCLUSION Our data suggest that Glut1 is a potentially novel and functional marker of CD4 T-cell activation during HIV infection. In addition, Glut1 expression on CD4 T cells may be exploited as a prognostic marker for CD4 T-cell loss during HIV disease progression.
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Affiliation(s)
- Clovis S Palmer
- aCentre for Biomedical Research, Burnet Institute, Melbourne, Australia bInstituto de Investigaciones Biomédicas en Retrovirus y SIDA. Facultad de Medicina, Buenos Aires, Argentina cCentre for Population Health, Burnet Institute, Melbourne dLaboratory of Molecular Immunomodulation, School of Biomedical Sciences, Monash University, Clayton eCellular and Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute fDepartment of Infectious Diseases, Monash University gInfectious Diseases Department, The Alfred hospital, Melbourne, Australia hDepartment of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois iDivision of Experimental Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California, USA
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