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Malambane G, Madumane K, Sewelo LT, Batlang U. Drought stress tolerance mechanisms and their potential common indicators to salinity, insights from the wild watermelon (Citrullus lanatus): A review. FRONTIERS IN PLANT SCIENCE 2023; 13:1074395. [PMID: 36815012 PMCID: PMC9939662 DOI: 10.3389/fpls.2022.1074395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 11/25/2022] [Indexed: 06/18/2023]
Abstract
Climate change has escalated the effect of drought on crop production as it has negatively altered the environmental condition. Wild watermelon grows abundantly in the Kgalagadi desert even though the environment is characterized by minimal rainfall, high temperatures and intense sunshine during growing season. This area is also characterized by sandy soils with low water holding capacity, thus bringing about drought stress. Drought stress affects crop productivity through its effects on development and physiological functions as dictated by molecular responses. Not only one or two physiological process or genes are responsible for drought tolerance, but a combination of various factors do work together to aid crop tolerance mechanism. Various studies have shown that wild watermelon possess superior qualities that aid its survival in unfavorable conditions. These mechanisms include resilient root growth, timely stomatal closure, chlorophyll fluorescence quenching under water deficit as key physiological responses. At biochemical and molecular level, the crop responds through citrulline accumulation and expression of genes associated with drought tolerance in this species and other plants. Previous salinity stress studies involving other plants have identified citrulline accumulation and expression of some of these genes (chloroplast APX, Type-2 metallothionein), to be associated with tolerance. Emerging evidence indicates that the upstream of functional genes are the transcription factor that regulates drought and salinity stress responses as well as adaptation. In this review we discuss the drought tolerance mechanisms in watermelons and some of its common indicators to salinity at physiological, biochemical and molecular level.
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Chavan S, Khuperkar D, Lonare A, Panigrahi S, Bellare J, Rapole S, Seshadri V, Joseph J. RanGTPase links nucleo-cytoplasmic transport to the recruitment of cargoes into small extracellular vesicles. Cell Mol Life Sci 2022; 79:392. [PMID: 35779171 PMCID: PMC11071952 DOI: 10.1007/s00018-022-04422-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 11/24/2022]
Abstract
Small extracellular vesicle (sEV)-mediated intercellular communication regulates multiple aspects of growth and development in multicellular organisms. However, the mechanism underlying cargo recruitment into sEVs is currently unclear. We show that the key nucleo-cytoplasmic transport (NCT) protein-RanGTPase, in its GTP-bound form (RanGTP), is enriched in sEVs secreted by mammalian cells. This recruitment of RanGTP into sEVs depends on the export receptor CRM1 (also called XPO1). The recruitment of GAPDH, a candidate cargo protein, into sEVs is regulated by the RanGTP-CRM1axis in a nuclear export signal (NES)-dependent manner. Perturbation of NCT through overexpression or depletion of nuclear transport components affected the recruitment of Ran, CRM1 and GAPDH into sEVs. Our studies, thus, suggest a link between NCT, particularly the Ran-CRM1 axis, and recruitment of NES-containing cargoes into the sEVs. Collectively, these findings implicate RanGTPase as a link between NCT and sEV mediated intercellular communication.
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Affiliation(s)
- Sakalya Chavan
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007, India
| | - Deepak Khuperkar
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007, India
- UK Dementia Research Institute at King's College London, London and University of Cambridge, Cambridge, UK
| | - Akshay Lonare
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007, India
| | - Swagatika Panigrahi
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007, India
| | - Jayesh Bellare
- Department of Chemical Engineering and Wadhwani Research Centre for Bioengineering, IIT Bombay, Mumbai, 400079, India
| | - Srikanth Rapole
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007, India
| | - Vasudevan Seshadri
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007, India
| | - Jomon Joseph
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007, India.
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Cao Y, Liu K, Xiong Y, Zhao C, Liu L. Increased expression of fragmented tRNA promoted neuronal necrosis. Cell Death Dis 2021; 12:823. [PMID: 34462418 PMCID: PMC8405691 DOI: 10.1038/s41419-021-04108-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 06/26/2021] [Accepted: 06/30/2021] [Indexed: 02/07/2023]
Abstract
Neuronal necrosis induced by excessive glutamate release is well known to contribute morbidity and mortality in ischemic stroke. Over the past decades, strategies on targeting glutamate receptor did not achieve desirable clinical outcomes. Finding the downstream mechanism of the glutamate receptor activation may provide new targets to suppress the cell death. Previously, our study demonstrated that the increase of H3K4 trimethylation (H3K4me3) played a key detrimental role on neuronal necrosis; however, the mechanism of this histone modification is unclear. Through a genome-wide small RNA sequencing, we identified several tRNA-derived fragments (tRFs) and piwi-interacting RNA (piRNAs) species were enriched in glutamate-induced neuronal necrosis in rat primary neuron cultures, and this enrichment was dependent on the H3K4me3 increase. Strikingly, when we transfected several synthesized tRFs and piRNA species into neurons, the tRFs but not the piRNAs induced neuron swelling and death. The cell death morphology recapitulated neuronal necrosis induced by glutamate. For the cytotoxic effect of tRFs, our data suggested that protein synthesis was inhibited likely through induction of ribosomal stalling. By proteomic analysis of tRFs effect, the most affected pathway was enriched in the mitochondrial metabolism. Consistently, mitochondrial fragmentation was increased in neuronal necrosis, and suppression of mitochondrial fission by genetic manipulation or drug rescued neuronal necrosis. Using our previously established Drosophila model of neuronal necrosis, we found that inhibition of small RNA transcription, blocking RNA transport from nucleus to cytosol, or knocking down Ago1/2 to suppress the RNA interference effect, all rescued the fly death, suggesting transcription and processing of small RNAs contribute to neuronal necrosis. Together, these results indicate that the abnormal transcription of tRFs may play a key role downstream of the H3K4me3 increase. This provides a potential new strategy to suppress neuronal necrosis.
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Affiliation(s)
- Yanyan Cao
- grid.24696.3f0000 0004 0369 153XDepartment of Biochemistry and Molecular Biology School of Basic Medicine, Capital Medical University, Youanmen, Beijing, China ,grid.453074.10000 0000 9797 0900Department of Neurology, First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, China
| | - Kai Liu
- grid.49470.3e0000 0001 2331 6153College of Life Sciences, Wuhan University, Wuhan, China
| | - Ying Xiong
- grid.24696.3f0000 0004 0369 153XDepartment of Biochemistry and Molecular Biology School of Basic Medicine, Capital Medical University, Youanmen, Beijing, China
| | - Chunyue Zhao
- grid.64939.310000 0000 9999 1211Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, Beijing, China
| | - Lei Liu
- grid.24696.3f0000 0004 0369 153XDepartment of Biochemistry and Molecular Biology School of Basic Medicine, Capital Medical University, Youanmen, Beijing, China
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Murphy RJ, Buenzli PR, Tambyah TA, Thompson EW, Hugo HJ, Baker RE, Simpson MJ. The role of mechanical interactions in EMT. Phys Biol 2021; 18. [PMID: 33789261 DOI: 10.1088/1478-3975/abf425] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/31/2021] [Indexed: 02/07/2023]
Abstract
The detachment of cells from the boundary of an epithelial tissue and the subsequent invasion of these cells into surrounding tissues is important for cancer development and wound healing, and is strongly associated with the epithelial-mesenchymal transition (EMT). Chemical signals, such as TGF-β, produced by surrounding tissue can be uptaken by cells and induce EMT. In this work, we present a novel cell-based discrete mathematical model of mechanical cellular relaxation, cell proliferation, and cell detachment driven by chemically-dependent EMT in an epithelial tissue. A continuum description of the model is then derived in the form of a novel nonlinear free boundary problem. Using the discrete and continuum models we explore how the coupling of chemical transport and mechanical interactions influences EMT, and postulate how this could be used to help control EMT in pathological situations.
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Affiliation(s)
- Ryan J Murphy
- Queensland University of Technology, Mathematical Sciences, Brisbane, Australia
| | - Pascal R Buenzli
- Queensland University of Technology, Mathematical Sciences, Brisbane, Australia
| | - Tamara A Tambyah
- Queensland University of Technology, Mathematical Sciences, Brisbane, Australia
| | - Erik W Thompson
- Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, Australia.,Queensland University of Technology, School of Biomedical Sciences, Faculty of Health, Brisbane, Australia.,Translational Research Institute, Brisbane, Australia
| | - Honor J Hugo
- Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, Australia.,Queensland University of Technology, School of Biomedical Sciences, Faculty of Health, Brisbane, Australia.,Translational Research Institute, Brisbane, Australia
| | - Ruth E Baker
- University of Oxford, Mathematical Institute, Oxford, United Kingdom
| | - Matthew J Simpson
- Queensland University of Technology, Mathematical Sciences, Brisbane, Australia
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Tambyah TA, Murphy RJ, Buenzli PR, Simpson MJ. A free boundary mechanobiological model of epithelial tissues. Proc Math Phys Eng Sci 2020; 476:20200528. [PMID: 33362419 PMCID: PMC7735320 DOI: 10.1098/rspa.2020.0528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/21/2020] [Indexed: 12/12/2022] Open
Abstract
In this study, we couple intracellular signalling and cell-based mechanical properties to develop a novel free boundary mechanobiological model of epithelial tissue dynamics. Mechanobiological coupling is introduced at the cell level in a discrete modelling framework, and new reaction-diffusion equations are derived to describe tissue-level outcomes. The free boundary evolves as a result of the underlying biological mechanisms included in the discrete model. To demonstrate the accuracy of the continuum model, we compare numerical solutions of the discrete and continuum models for two different signalling pathways. First, we study the Rac-Rho pathway where cell- and tissue-level mechanics are directly related to intracellular signalling. Second, we study an activator-inhibitor system which gives rise to spatial and temporal patterning related to Turing patterns. In all cases, the continuum model and free boundary condition accurately reflect the cell-level processes included in the discrete model.
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Affiliation(s)
| | | | | | - Matthew J. Simpson
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia
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Boudhraa Z, Carmona E, Provencher D, Mes-Masson AM. Ran GTPase: A Key Player in Tumor Progression and Metastasis. Front Cell Dev Biol 2020; 8:345. [PMID: 32528950 PMCID: PMC7264121 DOI: 10.3389/fcell.2020.00345] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Ran (Ras-related nuclear protein) GTPase is a member of the Ras superfamily. Like all the GTPases, Ran cycles between an active (GTP-bound) and inactive (GDP-bound) state. However, Ran lacks the CAAX motif at its C-terminus, a feature of other small GTPases that ensures a plasma membrane localization, and largely traffics between the nucleus and the cytoplasm. Ran regulates nucleo-cytoplasmic transport of molecules through the nuclear pore complex and controls cell cycle progression through the regulation of microtubule polymerization and mitotic spindle formation. The disruption of Ran expression has been linked to cancer at different levels - from cancer initiation to metastasis. In the present review, we discuss the contribution of Ran in the acquisition of three hallmarks of cancer, namely, proliferative signaling, resistance to apoptosis, and invasion/metastasis, and highlight its prognostic value in cancer patients. In addition, we discuss the use of this GTPase as a therapeutic target in cancer.
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Affiliation(s)
- Zied Boudhraa
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada
| | - Euridice Carmona
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada
| | - Diane Provencher
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada.,Division of Gynecologic Oncology, Université de Montréal, Montreal, QC, Canada
| | - Anne-Marie Mes-Masson
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.,Institut du Cancer de Montréal (ICM), Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
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Lee Y, Ahn EH, Ryu CS, Kim JO, An HJ, Cho SH, Kim JH, Kim YR, Lee WS, Kim NK. Association between microRNA machinery gene polymorphisms and recurrent implantation failure. Exp Ther Med 2020; 19:3113-3123. [PMID: 32226488 PMCID: PMC7092926 DOI: 10.3892/etm.2020.8556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/29/2020] [Indexed: 12/11/2022] Open
Abstract
The present study aimed to investigate the potential association of five miRNA machinery gene polymorphisms (DICER1 rs3742330A>G, DROSHA rs10719T>C, RAN rs14035C>T, XPO5 rs11077A>C and DGCR8 rs417309G>A) with recurrent implantation failure (RIF), a clinical condition in which good-quality embryos repeatedly fail to implant following two or more in vitro fertilization cycles, and its associated risk factors in Korean women. Therefore, the present study performed genotype analysis and assessed the frequency of these miRNA gene polymorphisms in patients diagnosed with RIF (n=119) and randomly selected controls (n=210) with at least one live birth and no history of pregnancy loss. The DROSHA rs10719T>C and RAN rs14035C>T polymorphisms were identified to be significantly associated with decreased prevalence of RIF. Additionally, the DROSHA rs10719 TC and the RAN rs14035 CT genotypes were present at significantly lower frequencies in the RIF group than in the control group (adjusted odds ratio=0.550; 95% CI, 0.339-0.893; P=0.016; and adjusted odds ratio=0.590; 95% CI, 0.363-0.958; P=0.033, respectively). Furthermore, the combined RAN rs14035 CT+TT genotype was observed to be associated with decreased RIF prevalence (adjusted odds ratio=0.616; 95% CI, 0.386-0.982; P=0.042). Genotype combination analysis for the various miRNA polymorphisms revealed that the DROSHA TC genotype exhibited a highly significant negative association with RIF prevalence when combined with the RAN CT genotype (adjusted odds ratio=0.314; 95% CI, 0.147-0.673; P=0.003; false discovery rate-adjusted P=0.023). The present study revealed an association between the DROSHA rs10719 and RAN rs14035 3'UTR polymorphisms and decreased risk of RIF in Korean women, which suggests that these gene polymorphisms could represent potential markers for predicting RIF risk.
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Affiliation(s)
- Yubin Lee
- Department of Obstetrics and Gynecology, Fertility Center of CHA Gangnam Medical Center, CHA University, Seoul 06135, Republic of Korea.,CHA Fertility Center, Seoul Station, Seoul 04637, Republic of Korea
| | - Eun Hee Ahn
- Department of Obstetrics and Gynecology, Fertility Center of CHA Gangnam Medical Center, CHA University, Seoul 06135, Republic of Korea
| | - Chang Soo Ryu
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
| | - Jung Oh Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
| | - Hui Jeong An
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
| | - Sung Hwan Cho
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
| | - Ji Hyang Kim
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi 13497, Republic of Korea
| | - Young Ran Kim
- Department of Obstetrics and Gynecology, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi 13497, Republic of Korea
| | - Woo Sik Lee
- Department of Obstetrics and Gynecology, Fertility Center of CHA Gangnam Medical Center, CHA University, Seoul 06135, Republic of Korea
| | - Nam Keun Kim
- Department of Biomedical Science, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Republic of Korea
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8
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Ran promotes membrane targeting and stabilization of RhoA to orchestrate ovarian cancer cell invasion. Nat Commun 2019; 10:2666. [PMID: 31209254 PMCID: PMC6573066 DOI: 10.1038/s41467-019-10570-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 05/15/2019] [Indexed: 12/22/2022] Open
Abstract
Ran is a nucleocytoplasmic shuttle protein that is involved in cell cycle regulation, nuclear-cytoplasmic transport, and cell transformation. Ran plays an important role in cancer cell survival and cancer progression. Here, we show that, in addition to the nucleocytoplasmic localization of Ran, this GTPase is specifically associated with the plasma membrane/ruffles of ovarian cancer cells. Ran depletion has a drastic effect on RhoA stability and inhibits RhoA localization to the plasma membrane/ruffles and RhoA activity. We further demonstrate that the DEDDDL domain of Ran is required for the interaction with serine 188 of RhoA, which prevents RhoA degradation by the proteasome pathway. Moreover, the knockdown of Ran leads to a reduction of ovarian cancer cell invasion by impairing RhoA signalling. Our findings provide advanced insights into the mode of action of the Ran-RhoA signalling axis and may represent a potential therapeutic avenue for drug development to prevent ovarian tumour metastasis. Ran, a nucleus-cytoplasm shuttle protein, is implicated in cancer development and survival. Here, the authors show that Ran binds RhoA to impair its degradation and allow its localisation to the plasma membrane of ovarian cancer cells for tumour invasion.
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Sheng KL, Pridham KJ, Sheng Z, Lamouille S, Varghese RT. Functional Blockade of Small GTPase RAN Inhibits Glioblastoma Cell Viability. Front Oncol 2019; 8:662. [PMID: 30671385 PMCID: PMC6331428 DOI: 10.3389/fonc.2018.00662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/13/2018] [Indexed: 11/13/2022] Open
Abstract
Glioblastoma, the most common malignant tumor in the brain, lacks effective treatments and is currently incurable. To identify novel drug targets for this deadly cancer, the publicly available results of RNA interference screens from the Project Achilles database were analyzed. Ten candidate genes were identified as survival genes in 15 glioblastoma cell lines. RAN, member RAS oncogene family (RAN) was expressed in glioblastoma at the highest level among all candidates based upon cDNA microarray data. However, Kaplan-Meier survival analysis did not show any correlation between RAN mRNA levels and patient survival. Because RAN is a small GTPase that regulates nuclear transport controlled by karyopherin subunit beta 1 (KPNB1), RAN was further analyzed together with KPNB1. Indeed, GBM patients with high levels of RAN also had more KPNB1 and levels of KPNB1 alone did not relate to patient prognosis. Through a Cox multivariate analysis, GBM patients with high levels of RAN and KPNB1 showed significantly shorter life expectancy when temozolomide and promoter methylation of O6-methylguanine DNA methyltransferase were used as covariates. These results indicate that RAN and KPNB1 together are associated with drug resistance and GBM poor prognosis. Furthermore, the functional blockade of RAN and KPNB1 by importazole remarkably suppressed cell viability and activated apoptosis in GBM cells expressing high levels of RAN, while having a limited effect on astrocytes and GBM cells with undetectable RAN. Together, our results demonstrate that RAN activity is important for GBM survival and the functional blockade of RAN/KPNB1 is an appealing therapeutic approach.
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Affiliation(s)
- Kevin L Sheng
- Fralin Biomedical Research Institute at VTC, Roanoke, VA, United States
| | - Kevin J Pridham
- Fralin Biomedical Research Institute at VTC, Roanoke, VA, United States
| | - Zhi Sheng
- Fralin Biomedical Research Institute at VTC, Roanoke, VA, United States.,Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, United States.,Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA, United States.,Wake Forest Baptist Comprehensive Cancer Center, Winston-Salem, NC, United States.,Faculty of Health Science, Virginia Tech, Blacksburg, VA, United States
| | - Samy Lamouille
- Fralin Biomedical Research Institute at VTC, Roanoke, VA, United States.,Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA, United States.,Department of Biological Sciences, College of Science, Virginia Tech, Blacksburg, VA, United States
| | - Robin T Varghese
- Department of Biological Affairs and Research, Edward Via College of Osteopathic Medicine, Blacksburg, VA, United States
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Vijayaraghavan B, Jafferali MH, Figueroa RA, Hallberg E. Samp1, a RanGTP binding transmembrane protein in the inner nuclear membrane. Nucleus 2017; 7:415-23. [PMID: 27541860 PMCID: PMC5039005 DOI: 10.1080/19491034.2016.1220465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Samp1 is a transmembrane protein of the inner nuclear membrane (INM), which interacts with the nuclear lamina and the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex in interphase and during mitosis, it localizes to the mitotic spindle. Samp1 was recently found to coprecipitate a protein complex containing Ran, a GTPase with fundamental regulatory functions both in interphase and in mitosis. To investigate the interaction between Samp1 and Ran in further detail, we have designed and expressed recombinant fusion proteins of the Chaetomium thermophilum homolog of Samp1 (Ct.Samp1) and human Ran. Pulldown experiments show that Samp1 binds directly to Ran and that Samp1 binds better to RanGTP compared to RanGDP. Samp1 also preferred RanGTP over RanGDP in living tsBN2 cells. We also show that the Ran binding domain is located between amino acids 75–135 in the nucleoplasmically exposed N-terminal tail of Samp1. This domain is unique for Samp1, without homology in any other proteins in fungi or metazoa. Samp1 is the first known transmembrane protein that binds to Ran and could provide a unique local binding site for RanGTP in the INM. Samp1 overexpression resulted in increased Ran concentrations in the nuclear periphery supporting this idea.
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Affiliation(s)
| | | | | | - Einar Hallberg
- a Department of Neurochemistry , Stockholm University , Stockholm , Sweden
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SNP Variation in MicroRNA Biogenesis Pathway Genes as a New Innovation Strategy for Alzheimer Disease Diagnostics. Alzheimer Dis Assoc Disord 2016; 30:203-9. [DOI: 10.1097/wad.0000000000000135] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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