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Looser ZJ, Faik Z, Ravotto L, Zanker HS, Jung RB, Werner HB, Ruhwedel T, Möbius W, Bergles DE, Barros LF, Nave KA, Weber B, Saab AS. Oligodendrocyte-axon metabolic coupling is mediated by extracellular K + and maintains axonal health. Nat Neurosci 2024; 27:433-448. [PMID: 38267524 PMCID: PMC10917689 DOI: 10.1038/s41593-023-01558-3] [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: 11/08/2022] [Accepted: 12/13/2023] [Indexed: 01/26/2024]
Abstract
The integrity of myelinated axons relies on homeostatic support from oligodendrocytes (OLs). To determine how OLs detect axonal spiking and how rapid axon-OL metabolic coupling is regulated in the white matter, we studied activity-dependent calcium (Ca2+) and metabolite fluxes in the mouse optic nerve. We show that fast axonal spiking triggers Ca2+ signaling and glycolysis in OLs. OLs detect axonal activity through increases in extracellular potassium (K+) concentrations and activation of Kir4.1 channels, thereby regulating metabolite supply to axons. Both pharmacological inhibition and OL-specific inactivation of Kir4.1 reduce the activity-induced axonal lactate surge. Mice lacking oligodendroglial Kir4.1 exhibit lower resting lactate levels and altered glucose metabolism in axons. These early deficits in axonal energy metabolism are associated with late-onset axonopathy. Our findings reveal that OLs detect fast axonal spiking through K+ signaling, making acute metabolic coupling possible and adjusting the axon-OL metabolic unit to promote axonal health.
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Affiliation(s)
- Zoe J Looser
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Zainab Faik
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Luca Ravotto
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Henri S Zanker
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - L Felipe Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.
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2
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Zhao X, Qi Y, Wu T, Cheng G. Phosphoproteomic Analysis of the Jejunum Tissue Response to Colostrum and Milk Feeding in Dairy Calves during the Passive Immunity Period. Animals (Basel) 2022; 13:ani13010145. [PMID: 36611753 PMCID: PMC9817995 DOI: 10.3390/ani13010145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/21/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Improvements in the feeding of calves are of increasing importance for the development of the dairy industry. While colostrum is essential for the health of newborn calves, knowledge of protein phosphorylation alterations in neonatal calves that are fed colostrum or mature milk is lacking. Here, mid-jejunum tissue samples were collected from calves that received colostrum or milk. Subsequently, the jejunum phosphoproteome was analyzed using a phosphopeptide enrichment method, i.e., titanium immobilized metal ion affinity chromatography, coupled with liquid chromatography-tandem mass spectrometry. A total of 2093 phosphopeptides carrying unique 1851 phosphorylation sites corresponding to 1180 phosphoproteins were identified. Of the 1180 phosphoproteins, 314 phosphorylation sites on 241 proteins were differentially expressed between the groups. Gene ontology analysis indicated that the phosphoproteins were strongly associated with developmental and macromolecule metabolic processes, signal transduction, and responses to stimuli and insulin. Pathway analysis showed that the spliceosome, Hippo, insulin, and neurotrophin signaling pathways were enriched. These results reveal the expression pattern and changes in the function of phosphoproteins in bovine jejunum tissues under different feeding conditions and provide further insights into the crucial role of colostrum feeding during the early stages of life.
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Affiliation(s)
- Xiaowei Zhao
- Correspondence: ; Tel.: +86-551-65146065; Fax: +86-551-62160275
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3
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Zhao XW, Zhu HL, Qi YX, Wu T, Huang DW, Cheng GL, Yang YX, Bu DP, Hu H, Meng LF. Regulatory role of phosphoproteins in the development of bovine small intestine during early life. J Dairy Sci 2022; 105:9240-9252. [PMID: 36175223 DOI: 10.3168/jds.2022-21983] [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: 02/17/2022] [Accepted: 06/20/2022] [Indexed: 11/19/2022]
Abstract
The small intestine is the primary site of nutrient digestion and absorption, which plays a key role in the survival of neonatal calves. A comprehensive assessment of the phosphoproteomic changes in the small intestine of neonatal calves is unavailable; therefore, we used phosphopeptide enrichment coupled with liquid chromatography-tandem mass spectrometry to investigate the changes in the phosphoproteome profile in the bovine small intestine during the first 36 h of life. Twelve neonatal male calves were assigned to one of the following groups: (1) calves not fed colostrum and slaughtered approximately 2 h postpartum (n = 3), (2) calves fed colostrum at 1 to 2 h and slaughtered 8 h postpartum (n = 3), (3) calves fed 2 colostrum meals (at 1-2 and 10-12 h) and slaughtered 24 h postpartum (n = 3), (4) calves fed 3 colostrum meals (at 1-2, 10-12, and 22-24 h) and slaughtered 36 h postpartum (n = 3). Mid-duodenal, jejunal, and ileal samples of the calves were collected after slaughter. We identified 1,678 phosphoproteins with approximately 3,080 phosphosites, which were mainly Ser (89.9%), Thr (9.8%), and Tyr (0.3%) residues; they belonged to the prodirected (52.9%), basic (20.4%), acidic (16.6%), and Tyr-directed (1.7%) motif categories. The regional differentially expressed phosphoproteins included zonula occludens 2, sorting nexin 12, and protein kinase C, which are mainly associated with developmental processes, intracellular transport, vesicle-mediated transport, and immune system process. They are enriched in the endocytosis, tight junction, insulin signaling, and focal adhesion pathways. The temporal differentially expressed phosphoproteins included occludin, epsin 1, and bridging integrator 1, which were mainly associated with macromolecule metabolic process, cell adhesion, and growth. They were enriched in the spliceosomes, adherens junctions, and tight junctions. The observed changes in the phosphoproteins in the tissues of small intestine suggest the protein phosphorylation plays an important role in nutrient transport and immune response of calves during early life, which needs to be confirmed in a larger study.
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Affiliation(s)
- X W Zhao
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - H L Zhu
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Y X Qi
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - T Wu
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - D W Huang
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - G L Cheng
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Y X Yang
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China.
| | - D P Bu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences of Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - H Hu
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
| | - L F Meng
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
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4
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Bai R, Zhang T, Gao Y, Shu T, Zhou Y, Wang F, Chang X, Tang W, Zhu Y, Han X. Rab31, a receptor of advanced glycation end products (RAGE) interacting protein, inhibits AGE induced pancreatic β-cell apoptosis through the pAKT/BCL2 pathway. Endocr J 2022; 69:1015-1026. [PMID: 35314532 DOI: 10.1507/endocrj.ej21-0594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Receptor of advanced glycation end products (RAGE) mediates diverse signal transduction following ligand stimulation and plays an important role in diabetes complications and aging associated disease. We have previously verified that advanced glycation end products (AGE) bind to RAGE to cause pancreatic β-cell apoptosis through the mitochondrial pathway. However, the direct interacting protein(s) of RAGE in β cells has never been appreciated. In the present study, we utilized GST pull-down assay combined with mass spectrometry to identify the interacting proteins of the RAGE intracellular domain (C-terminal 43 amino acid of RAGE). Overall four RAGE interacting proteins, including Rab31, were identified with scores over 160. Rab31 was detected in three β-cell lines and confirmed to have interacted with RAGE via co-immunoprecipitation and immunostaining assays. This interaction was further enhanced by glycation-serum (GS) stimulation due to membrane distribution of Rab31 following treatment with GS. We further confirmed that Rab31 promoted RAGE endocytosis and inhibited GS-induced β-cell apoptosis through the pAKT/BCL2 pathway. These findings reveal a new RAGE interaction protein Rab31 that prevents AGE/RAGE-induced pancreatic β-cell apoptosis. Rab31 is therefore a promising therapeutic target for preserving functional β cells under diabetes conditions.
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Affiliation(s)
- Rongjie Bai
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing 211166, China
| | - Tao Zhang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing 211166, China
| | - Yan Gao
- Institute of Suzhou Biobank, Suzhou Center for Disease Prevention and Control, Suzhou 215004, China
- Suzhou Institute of Advanced Study in Public Health, Gusu School, Nanjing Medical University, Suzhou 215004, China
| | - Tingting Shu
- Department of Endocrinology, Geriatric Hospital of Nanjing Medical University, Nanjing 210024, China
| | - Yuncai Zhou
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing 211166, China
| | - Fuqiang Wang
- Analysis Center, Nanjing Medical University, Nanjing 210029, China
| | - Xiaoai Chang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing 211166, China
| | - Wei Tang
- Department of Endocrinology, Geriatric Hospital of Nanjing Medical University, Nanjing 210024, China
| | - Yunxia Zhu
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing 211166, China
| | - Xiao Han
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing 211166, China
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5
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Defective RAB31-mediated megakaryocytic early endosomal trafficking of VWF, EGFR, and M6PR in RUNX1 deficiency. Blood Adv 2022; 6:5100-5112. [PMID: 35839075 PMCID: PMC9631641 DOI: 10.1182/bloodadvances.2021006945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 06/13/2022] [Indexed: 11/20/2022] Open
Abstract
RAB31 is a RUNX1 target; regulates VWF, epidermal growth factor receptor, and mannose-6-phosphate trafficking; and is downregulated in RHD. EE and vesicle trafficking defects induced by RAB31 downregulation likely contribute to α-granule defects with RUNX1 mutation.
Transcription factor RUNX1 is a master regulator of hematopoiesis and megakaryopoiesis. RUNX1 haplodeficiency (RHD) is associated with thrombocytopenia and platelet granule deficiencies and dysfunction. Platelet profiling of our study patient with RHD showed decreased expression of RAB31, a small GTPase whose cell biology in megakaryocytes (MKs)/platelets is unknown. Platelet RAB31 messenger RNA was decreased in the index patient and in 2 additional patients with RHD. Promoter-reporter studies using phorbol 12-myristate 13-acetate–treated megakaryocytic human erythroleukemia cells revealed that RUNX1 regulates RAB31 via binding to its promoter. We investigated RUNX1 and RAB31 roles in endosomal dynamics using immunofluorescence staining for markers of early endosomes (EEs; early endosomal autoantigen 1) and late endosomes (CD63)/multivesicular bodies. Downregulation of RUNX1 or RAB31 (by small interfering RNA or CRISPR/Cas9) showed a striking enlargement of EEs, partially reversed by RAB31 reconstitution. This EE defect was observed in MKs differentiated from a patient-derived induced pluripotent stem cell line (RHD-iMKs). Studies using immunofluorescence staining showed that trafficking of 3 proteins with distinct roles (von Willebrand factor [VWF], a protein trafficked to α-granules; epidermal growth factor receptor; and mannose-6-phosphate) was impaired at the level of EE on downregulation of RAB31 or RUNX1. There was loss of plasma membrane VWF in RUNX1- and RAB31-deficient megakaryocytic human erythroleukemia cells and RHD-iMKs. These studies provide evidence that RAB31 is downregulated in RHD and regulates megakaryocytic vesicle trafficking of 3 major proteins with diverse biological roles. EE defect and impaired vesicle trafficking is a potential mechanism for the α-granule defects observed in RUNX1 deficiency.
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6
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Fazakerley DJ, Koumanov F, Holman GD. GLUT4 On the move. Biochem J 2022; 479:445-462. [PMID: 35147164 PMCID: PMC8883492 DOI: 10.1042/bcj20210073] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 12/16/2022]
Abstract
Insulin rapidly stimulates GLUT4 translocation and glucose transport in fat and muscle cells. Signals from the occupied insulin receptor are translated into downstream signalling changes in serine/threonine kinases within timescales of seconds, and this is followed by delivery and accumulation of the glucose transporter GLUT4 at the plasma membrane. Kinetic studies have led to realisation that there are distinct phases of this stimulation by insulin. There is a rapid initial burst of GLUT4 delivered to the cell surface from a subcellular reservoir compartment and this is followed by a steady-state level of continuing stimulation in which GLUT4 recycles through a large itinerary of subcellular locations. Here, we provide an overview of the phases of insulin stimulation of GLUT4 translocation and the molecules that are currently considered to activate these trafficking steps. Furthermore, we suggest how use of new experimental approaches together with phospho-proteomic data may help to further identify mechanisms for activation of these trafficking processes.
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Affiliation(s)
- Daniel J Fazakerley
- Metabolic Research Laboratories, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, U.K
| | - Francoise Koumanov
- Department for Health, Centre for Nutrition, Exercise, and Metabolism, University of Bath, Bath, Somerset BA2 7AY, U.K
| | - Geoffrey D Holman
- Department of Biology and Biochemistry, University of Bath, Bath, Somerset BA2 7AY, U.K
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7
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Phosphorylation of GAPVD1 Is Regulated by the PER Complex and Linked to GAPVD1 Degradation. Int J Mol Sci 2021; 22:ijms22073787. [PMID: 33917494 PMCID: PMC8038846 DOI: 10.3390/ijms22073787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 03/29/2021] [Accepted: 04/03/2021] [Indexed: 11/16/2022] Open
Abstract
Repressor protein period (PER) complexes play a central role in the molecular oscillator mechanism of the mammalian circadian clock. While the main role of nuclear PER complexes is transcriptional repression, much less is known about the functions of cytoplasmic PER complexes. We found with a biochemical screen for PER2-interacting proteins that the small GTPase regulator GTPase-activating protein and VPS9 domain-containing protein 1 (GAPVD1), which has been identified previously as a component of cytoplasmic PER complexes in mice, is also a bona fide component of human PER complexes. We show that in situ GAPVD1 is closely associated with casein kinase 1 delta (CSNK1D), a kinase that regulates PER2 levels through a phosphoswitch mechanism, and that CSNK1D regulates the phosphorylation of GAPVD1. Moreover, phosphorylation determines the kinetics of GAPVD1 degradation and is controlled by PER2 and a C-terminal autoinhibitory domain in CSNK1D, indicating that the regulation of GAPVD1 phosphorylation is a novel function of cytoplasmic PER complexes and might be part of the oscillator mechanism or an output function of the circadian clock.
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8
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Martínez-Aguilar L, Pérez-Ramírez C, Maldonado-Montoro MDM, Carrasco-Campos MI, Membrive-Jiménez C, Martínez-Martínez F, García-Collado C, Calleja-Hernández MÁ, Ramírez-Tortosa MC, Jiménez-Morales A. Effect of genetic polymorphisms on therapeutic response in multiple sclerosis relapsing-remitting patients treated with interferon-beta. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 785:108322. [PMID: 32800273 DOI: 10.1016/j.mrrev.2020.108322] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 07/02/2020] [Accepted: 07/02/2020] [Indexed: 11/30/2022]
Abstract
Treatment with interferon beta (IFNβ) is one of the first-line treatments for multiple sclerosis. In clinical practice, however, many patients present suboptimal response to IFNβ, with the proportion of non-responders ranging from 20 to 50%. This variable response can be affected by genetic factors, such as polymorphisms in the genes involved in the disease state, pharmacodynamics, metabolism or in the action mechanism of IFNβ, which can affect the efficacy of this drug. This review assesses the impact of pharmacogenetics studies on response to IFNβ treatment among patients diagnosed with relapsing-remitting multiple sclerosis (RRMS). The results suggest that the detection of polymorphisms in several genes (CD46, CD58, FHIT, IRF5, GAPVD1, GPC5, GRBRB3, MxA, PELI3 and ZNF697) could be used in the future as predictive markers of response to IFNβ treatment in patients diagnosed with RRMS. However, few studies have been carried out and they have been performed on small sample sizes, which makes it difficult to generalize the role of these genes in IFNβ treatment. Studies on large sample sizes with longer term follow-up are therefore required to confirm these results.
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Affiliation(s)
- Laura Martínez-Aguilar
- Department of Pharmacy and Pharmaceutical Technology. Social and Legal Assistance Pharmacy Section, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, s/n, 18071 Granada, Spain.
| | - Cristina Pérez-Ramírez
- Pharmacy Service. Pharmacogenetics Unit, University Hospital Virgen Macarena, Dr. Fedriani, 3, 41009 Sevilla, Spain.
| | | | - María Isabel Carrasco-Campos
- Pharmacy Service. Pharmacogenetics Unit, University Hospital Virgen de las Nieves, UGC Provincial de Farmacia de Granada, Avda. Fuerzas Armadas, 2, Spain.
| | - Cristina Membrive-Jiménez
- Pharmacy Service. Pharmacogenetics Unit, University Hospital Virgen de las Nieves, UGC Provincial de Farmacia de Granada, Avda. Fuerzas Armadas, 2, Spain.
| | - Fernando Martínez-Martínez
- Department of Pharmacy and Pharmaceutical Technology. Social and Legal Assistance Pharmacy Section, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, s/n, 18071 Granada, Spain.
| | - Carlos García-Collado
- Pharmacy Service. Pharmacogenetics Unit, University Hospital Virgen de las Nieves, UGC Provincial de Farmacia de Granada, Avda. Fuerzas Armadas, 2, Spain.
| | | | - María Carmen Ramírez-Tortosa
- Department of Biochemistry, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, s/n 18071 Granada, Spain.
| | - Alberto Jiménez-Morales
- Pharmacy Service. Pharmacogenetics Unit, University Hospital Virgen de las Nieves, UGC Provincial de Farmacia de Granada, Avda. Fuerzas Armadas, 2, Spain.
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9
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Batty MB, Schittenhelm RB, Dorin-Semblat D, Doerig C, Garcia-Bustos JF. Interaction of Plasmodium falciparum casein kinase 1 with components of host cell protein trafficking machinery. IUBMB Life 2020; 72:1243-1249. [PMID: 32356940 DOI: 10.1002/iub.2294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 03/25/2020] [Accepted: 04/09/2020] [Indexed: 12/21/2022]
Abstract
A pool of Plasmodium falciparum casein kinase 1 (PfCK1) has been shown to localize to the host red blood cell (RBC) membrane and be secreted to the extracellular medium during trophozoite stage of development. We attempted to identify mechanisms for secretion of PfCK1 and its appearance on the RBC membrane. We found that two host proteins with established functions in membrane trafficking in higher eukaryotes, GTPase-activating protein and Vps9 domain-containing protein 1 (GAPVD1), and Sorting nexin 22, consistently co-purify with PfCK1, suggesting that the parasite utilizes trafficking pathways previously thought to be inactive in RBCs. Furthermore, reciprocal immunoprecipitation experiments with GAPVD1 identified parasite proteins suggestive of a protein recycling pathway hitherto only described in higher eukaryotes. Thus, we have identified components of a trafficking pathway involving parasite proteins that act in concert with host proteins, and which we hypothesize mediates trafficking of PfCK1 to the RBC during infection.
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Affiliation(s)
- Mitchell B Batty
- Infection and Immunity Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Ralf B Schittenhelm
- Monash Proteomics & Metabolomics Facility, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Dominique Dorin-Semblat
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France
| | - Christian Doerig
- Infection and Immunity Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.,Centre for Chronic, Inflammatory and Infectious Diseases, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Jose F Garcia-Bustos
- Infection and Immunity Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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10
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Guillen RX, Beckley JR, Chen JS, Gould KL. CRISPR-mediated gene targeting of CK1δ/ε leads to enhanced understanding of their role in endocytosis via phosphoregulation of GAPVD1. Sci Rep 2020; 10:6797. [PMID: 32321936 PMCID: PMC7176688 DOI: 10.1038/s41598-020-63669-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 03/26/2020] [Indexed: 02/05/2023] Open
Abstract
Human casein kinase 1 delta (CK1δ) and epsilon (CK1ε) are members of a conserved family of abundant, ubiquitously expressed serine/threonine kinases that regulate multiple cellular processes including circadian rhythm and endocytosis. Here, we have investigated the localization and interactomes of endogenously tagged CK1δ and CK1ε during interphase and mitosis. CK1δ and CK1ε localize to centrosomes throughout the cell cycle, and in interphase cells to the nucleus, and in both a diffuse and punctate pattern in the cytoplasm. Also, for the first time, they were detected at the midbody during cell division. Mass spectrometry analysis identified a total of 181 proteins co-purifying with a Venus multifunctional (VM)-tagged CK1δ and/or CK1ε. GTPase-activating protein and VPS9 domain-containing protein 1 (GAPVD1), a protein required for efficient endocytosis, was consistently one of the most abundant interacting partners. We demonstrate that GAPVD1 is a substrate of CK1δ/ε with up to 38 phosphorylated residues in vitro and in vivo. Wildtype and a phosphomimetic mutant of GAPVD1, but not a phospho-ablating mutant, were able to rescue defects in transferrin and EGF internalization caused by loss of endogenous GAPVD1. Our results indicate that GAPVD1 is an important interacting partner and substrate of CK1δ/ε for endocytosis.
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Affiliation(s)
- Rodrigo X Guillen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Janel R Beckley
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.,Calico Group LLC, ProteoWorker, Nashville, TN, 32712, USA
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.
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11
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Ducommun S, Deak M, Zeigerer A, Göransson O, Seitz S, Collodet C, Madsen AB, Jensen TE, Viollet B, Foretz M, Gut P, Sumpton D, Sakamoto K. Chemical genetic screen identifies Gapex-5/GAPVD1 and STBD1 as novel AMPK substrates. Cell Signal 2019; 57:45-57. [PMID: 30772465 DOI: 10.1016/j.cellsig.2019.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 02/06/2023]
Abstract
AMP-activated protein kinase (AMPK) is a key regulator of cellular energy homeostasis, acting as a sensor of energy and nutrient status. As such, AMPK is considered a promising drug target for treatment of medical conditions particularly associated with metabolic dysfunctions. To better understand the downstream effectors and physiological consequences of AMPK activation, we have employed a chemical genetic screen in mouse primary hepatocytes in an attempt to identify novel AMPK targets. Treatment of hepatocytes with a potent and specific AMPK activator 991 resulted in identification of 65 proteins phosphorylated upon AMPK activation, which are involved in a variety of cellular processes such as lipid/glycogen metabolism, vesicle trafficking, and cytoskeleton organisation. Further characterisation and validation using mass spectrometry followed by immunoblotting analysis with phosphorylation site-specific antibodies identified AMPK-dependent phosphorylation of Gapex-5 (also known as GTPase-activating protein and VPS9 domain-containing protein 1 (GAPVD1)) on Ser902 in hepatocytes and starch-binding domain 1 (STBD1) on Ser175 in multiple cells/tissues. As new promising roles of AMPK as a key metabolic regulator continue to emerge, the substrates we identified could provide new mechanistic and therapeutic insights into AMPK-activating drugs in the liver.
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Affiliation(s)
- Serge Ducommun
- Nestlé Research, École Polytechnique Fédérale de Lausanne (EPFL) Innovation Park, bâtiment G, 1015 Lausanne, Switzerland; School of Life Sciences, EPFL, 1015 Lausanne, Switzerland
| | - Maria Deak
- Nestlé Research, École Polytechnique Fédérale de Lausanne (EPFL) Innovation Park, bâtiment G, 1015 Lausanne, Switzerland
| | - Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Olga Göransson
- Department of Experimental Medical Sciences, Lund University, 221 84 Lund, Sweden
| | - Susanne Seitz
- Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Caterina Collodet
- Nestlé Research, École Polytechnique Fédérale de Lausanne (EPFL) Innovation Park, bâtiment G, 1015 Lausanne, Switzerland; School of Life Sciences, EPFL, 1015 Lausanne, Switzerland
| | - Agnete B Madsen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Thomas E Jensen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Benoit Viollet
- Inserm, U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France; Université Paris Descartes, Sorbonne Paris cité, Paris, France
| | - Marc Foretz
- Inserm, U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France; Université Paris Descartes, Sorbonne Paris cité, Paris, France
| | - Philipp Gut
- Nestlé Research, École Polytechnique Fédérale de Lausanne (EPFL) Innovation Park, bâtiment G, 1015 Lausanne, Switzerland
| | - David Sumpton
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK
| | - Kei Sakamoto
- Nestlé Research, École Polytechnique Fédérale de Lausanne (EPFL) Innovation Park, bâtiment G, 1015 Lausanne, Switzerland; School of Life Sciences, EPFL, 1015 Lausanne, Switzerland.
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12
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Hermle T, Schneider R, Schapiro D, Braun DA, van der Ven AT, Warejko JK, Daga A, Widmeier E, Nakayama M, Jobst-Schwan T, Majmundar AJ, Ashraf S, Rao J, Finn LS, Tasic V, Hernandez JD, Bagga A, Jalalah SM, El Desoky S, Kari JA, Laricchia KM, Lek M, Rehm HL, MacArthur DG, Mane S, Lifton RP, Shril S, Hildebrandt F. GAPVD1 and ANKFY1 Mutations Implicate RAB5 Regulation in Nephrotic Syndrome. J Am Soc Nephrol 2018; 29:2123-2138. [PMID: 29959197 PMCID: PMC6065084 DOI: 10.1681/asn.2017121312] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/24/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of CKD. The discovery of monogenic causes of SRNS has revealed specific pathogenetic pathways, but these monogenic causes do not explain all cases of SRNS. METHODS To identify novel monogenic causes of SRNS, we screened 665 patients by whole-exome sequencing. We then evaluated the in vitro functional significance of two genes and the mutations therein that we discovered through this sequencing and conducted complementary studies in podocyte-like Drosophila nephrocytes. RESULTS We identified conserved, homozygous missense mutations of GAPVD1 in two families with early-onset NS and a homozygous missense mutation of ANKFY1 in two siblings with SRNS. GAPVD1 and ANKFY1 interact with the endosomal regulator RAB5. Coimmunoprecipitation assays indicated interaction between GAPVD1 and ANKFY1 proteins, which also colocalized when expressed in HEK293T cells. Silencing either protein diminished the podocyte migration rate. Compared with wild-type GAPVD1 and ANKFY1, the mutated proteins produced upon ectopic expression of GAPVD1 or ANKFY1 bearing the patient-derived mutations exhibited altered binding affinity for active RAB5 and reduced ability to rescue the knockout-induced defect in podocyte migration. Coimmunoprecipitation assays further demonstrated a physical interaction between nephrin and GAPVD1, and immunofluorescence revealed partial colocalization of these proteins in rat glomeruli. The patient-derived GAPVD1 mutations reduced nephrin-GAPVD1 binding affinity. In Drosophila, silencing Gapvd1 impaired endocytosis and caused mistrafficking of the nephrin ortholog. CONCLUSIONS Mutations in GAPVD1 and probably in ANKFY1 are novel monogenic causes of NS. The discovery of these genes implicates RAB5 regulation in the pathogenesis of human NS.
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Affiliation(s)
- Tobias Hermle
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
- Renal Division, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - David Schapiro
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Daniela A Braun
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amelie T van der Ven
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jillian K Warejko
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ankana Daga
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Eugen Widmeier
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Makiko Nakayama
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Tilman Jobst-Schwan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Shazia Ashraf
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jia Rao
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Laura S Finn
- Department of Pathology, Seattle Children's Hospital, University of Washington, Seattle, Washington
| | - Velibor Tasic
- Department of Pediatric Nephrology, Medical Faculty Skopje, University Children's Hospital, Skopje, Macedonia
| | - Joel D Hernandez
- Department of Pediatric Nephrology, Providence Sacred Heart Medical Center and Children's Hospital, Spokane, Washington
| | - Arvind Bagga
- Division of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | | | - Sherif El Desoky
- Pediatric Nephrology Center of Excellence and Pediatric Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Jameela A Kari
- Pediatric Nephrology Center of Excellence and Pediatric Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Kristen M Laricchia
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Monkol Lek
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Heidi L Rehm
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Daniel G MacArthur
- Broad Center for Mendelian Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut; and
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut; and
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, New York
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
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13
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Aspenström P. BAR Domain Proteins Regulate Rho GTPase Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1111:33-53. [PMID: 30151649 DOI: 10.1007/5584_2018_259] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The Bin-Amphiphysin-Rvs (BAR) domain is a membrane lipid binding domain present in a wide variety of proteins, often proteins with a role in Rho-regulated signaling pathways. BAR domains do not only confer binding to lipid bilayers, they also possess a membrane sculpturing ability and thereby directly control the topology of biomembranes. BAR domain-containing proteins participate in a plethora of physiological processes but the common denominator is their capacity to link membrane dynamics to actin dynamics and thereby integrate processes such as endocytosis, exocytosis, vesicle trafficking, cell morphogenesis and cell migration. The Rho family of small GTPases constitutes an important bridging theme for many BAR domain-containing proteins. This review article will focus predominantly on the role of BAR proteins as regulators or effectors of Rho GTPases and it will only briefly discuss the structural and biophysical function of the BAR domains.
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Affiliation(s)
- Pontus Aspenström
- Department of Microbiology, and Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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14
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Aryal RP, Kwak PB, Tamayo AG, Gebert M, Chiu PL, Walz T, Weitz CJ. Macromolecular Assemblies of the Mammalian Circadian Clock. Mol Cell 2017; 67:770-782.e6. [PMID: 28886335 PMCID: PMC5679067 DOI: 10.1016/j.molcel.2017.07.017] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/14/2017] [Accepted: 07/13/2017] [Indexed: 10/18/2022]
Abstract
The mammalian circadian clock is built on a feedback loop in which PER and CRY proteins repress their own transcription. We found that in mouse liver nuclei all three PERs, both CRYs, and Casein Kinase-1δ (CK1δ) are present together in an ∼1.9-MDa repressor assembly that quantitatively incorporates its CLOCK-BMAL1 transcription factor target. Prior to incorporation, CLOCK-BMAL1 exists in an ∼750-kDa complex. Single-particle electron microscopy (EM) revealed nuclear PER complexes purified from mouse liver to be quasi-spherical ∼40-nm structures. In the cytoplasm, PERs, CRYs, and CK1δ were distributed into several complexes of ∼0.9-1.1 MDa that appear to constitute an assembly pathway regulated by GAPVD1, a cytoplasmic trafficking factor. Single-particle EM of two purified cytoplasmic PER complexes revealed ∼20-nm and ∼25-nm structures, respectively, characterized by flexibly tethered globular domains. Our results define the macromolecular assemblies comprising the circadian feedback loop and provide an initial structural view of endogenous eukaryotic clock machinery.
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Affiliation(s)
- Rajindra P Aryal
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Pieter Bas Kwak
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Alfred G Tamayo
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Michael Gebert
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Po-Lin Chiu
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, Rockefeller University, New York, NY 10065, USA
| | - Charles J Weitz
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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15
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Dahlman I, Belarbi Y, Laurencikiene J, Pettersson AM, Arner P, Kulyté A. Comprehensive functional screening of miRNAs involved in fat cell insulin sensitivity among women. Am J Physiol Endocrinol Metab 2017; 312:E482-E494. [PMID: 28270439 DOI: 10.1152/ajpendo.00251.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 01/18/2017] [Accepted: 02/22/2017] [Indexed: 01/12/2023]
Abstract
The key pathological link between obesity and type 2 diabetes is insulin resistance, but the molecular mechanisms are not entirely identified. micro-RNAs (miRNA) are dysregulated in obesity and may contribute to insulin resistance. Our objective was to detect and functionally investigate miRNAs linked to insulin sensitivity in human subcutaneous white adipose tissue (scWAT). Subjects were selected based on the insulin-stimulated lipogenesis response of subcutaneous adipocytes. Global miRNA profiling was performed in abdominal scWAT of 18 obese insulin-resistance (OIR), 21 obese insulin-sensitive (OIS), and 9 lean women. miRNAs demonstrating differential expression between OIR and OIS women were overexpressed in human in vitro-differentiated adipocytes followed by assessment of lipogenesis and identification of miRNA targets by measuring mRNA/protein expression and 3'-untranslated region analysis. Eleven miRNAs displayed differential expression between OIR and OIS states. Overexpression of miR-143-3p and miR-652-3p increased insulin-stimulated lipogenesis in human in vitro differentiated adipocytes and directly or indirectly affected several genes/proteins involved in insulin signaling at transcriptional or posttranscriptional levels. Adipose expression of miR-143-3p and miR-652-3p was positively associated with insulin-stimulated lipogenesis in scWAT independent of body mass index. In conclusion, miR-143-3p and miR-652-3p are linked to scWAT insulin resistance independent of obesity and influence insulin-stimulated lipogenesis by interacting at different steps with insulin-signaling pathways.
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Affiliation(s)
- Ingrid Dahlman
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Yasmina Belarbi
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Jurga Laurencikiene
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Annie M Pettersson
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Peter Arner
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Agné Kulyté
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
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16
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Uhm M, Bazuine M, Zhao P, Chiang SH, Xiong T, Karunanithi S, Chang L, Saltiel AR. Phosphorylation of the exocyst protein Exo84 by TBK1 promotes insulin-stimulated GLUT4 trafficking. Sci Signal 2017; 10:10/471/eaah5085. [PMID: 28325821 DOI: 10.1126/scisignal.aah5085] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Insulin stimulates glucose uptake through the translocation of the glucose transporter GLUT4 to the plasma membrane. The exocyst complex tethers GLUT4-containing vesicles to the plasma membrane, a process that requires the binding of the G protein (heterotrimeric guanine nucleotide-binding protein) RalA to the exocyst complex. We report that upon activation of RalA, the protein kinase TBK1 phosphorylated the exocyst subunit Exo84. Knockdown of TBK1 blocked insulin-stimulated glucose uptake and GLUT4 translocation; knockout of TBK1 in adipocytes blocked insulin-stimulated glucose uptake; and ectopic overexpression of a kinase-inactive mutant of TBK1 reduced insulin-stimulated glucose uptake in 3T3-L1 adipocytes. The phosphorylation of Exo84 by TBK1 reduced its affinity for RalA and enabled its release from the exocyst. Overexpression of a kinase-inactive mutant of TBK1 blocked the dissociation of the TBK1/RalA/exocyst complex, and treatment of 3T3-L1 adipocytes with specific inhibitors of TBK1 reduced the rate of complex dissociation. Introduction of phosphorylation-mimicking or nonphosphorylatable mutant forms of Exo84 blocked insulin-stimulated GLUT4 translocation. Thus, these data indicate that TBK1 controls GLUT4 vesicle engagement and disengagement from the exocyst, suggesting that exocyst components not only constitute a tethering complex for the GLUT4 vesicle but also act as "gatekeepers" controlling vesicle fusion at the plasma membrane.
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Affiliation(s)
- Maeran Uhm
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Merlijn Bazuine
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peng Zhao
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Institute for Diabetes and Metabolic Health, Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shian-Huey Chiang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tingting Xiong
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Louise Chang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alan R Saltiel
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA. .,Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.,Institute for Diabetes and Metabolic Health, Departments of Medicine and Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
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17
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CMTM3 decreases EGFR expression and EGF-mediated tumorigenicity by promoting Rab5 activity in gastric cancer. Cancer Lett 2017; 386:77-86. [DOI: 10.1016/j.canlet.2016.11.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/27/2016] [Accepted: 11/10/2016] [Indexed: 02/06/2023]
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18
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Tunduguru R, Thurmond DC. Promoting Glucose Transporter-4 Vesicle Trafficking along Cytoskeletal Tracks: PAK-Ing Them Out. Front Endocrinol (Lausanne) 2017; 8:329. [PMID: 29209279 PMCID: PMC5701999 DOI: 10.3389/fendo.2017.00329] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/06/2017] [Indexed: 12/27/2022] Open
Abstract
Glucose is the principal cellular energy source in humans and maintenance of glucose homeostasis is critical for survival. Glucose uptake into peripheral skeletal muscle and adipose tissues requires the trafficking of vesicles containing glucose transporter-4 (GLUT4) from the intracellular storage compartments to the cell surface. Trafficking of GLUT4 storage vesicles is initiated via the canonical insulin signaling cascade in skeletal muscle and fat cells, as well as via exercise-induced contraction in muscle cells. Recent studies have elucidated steps in the signaling cascades that involve remodeling of the cytoskeleton, a process that underpins the mechanical movement of GLUT4 vesicles. This review is focused upon an alternate phosphoinositide-3 kinase-dependent pathway involving Ras-related C3 botulinum toxin substrate 1 signaling through the p21-activated kinase p21-activated kinase 1 and showcases related signaling events that co-regulate both the depolymerization and re-polymerization of filamentous actin. These new insights provide an enriched understanding into the process of glucose transport and yield potential new targets for interventions aimed to improve insulin sensitivity and remediate insulin resistance, pre-diabetes, and the progression to type 2 diabetes.
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Affiliation(s)
- Ragadeepthi Tunduguru
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute of City of Hope, Duarte, CA, United States
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute of City of Hope, Duarte, CA, United States
- *Correspondence: Debbie C. Thurmond,
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19
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Zhou X, Shentu P, Xu Y. Spatiotemporal Regulators for Insulin-Stimulated GLUT4 Vesicle Exocytosis. J Diabetes Res 2017; 2017:1683678. [PMID: 28529958 PMCID: PMC5424486 DOI: 10.1155/2017/1683678] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/21/2017] [Accepted: 04/03/2017] [Indexed: 11/30/2022] Open
Abstract
Insulin increases glucose uptake and storage in muscle and adipose cells, which is accomplished through the mobilization of intracellular GLUT4 storage vesicles (GSVs) to the cell surface upon stimulation. Importantly, the dysfunction of insulin-regulated GLUT4 trafficking is strongly linked with peripheral insulin resistance and type 2 diabetes in human. The insulin signaling pathway, key signaling molecules involved, and precise trafficking itinerary of GSVs are largely identified. Understanding the interaction between insulin signaling molecules and key regulatory proteins that are involved in spatiotemporal regulation of GLUT4 vesicle exocytosis is of great importance to explain the pathogenesis of diabetes and may provide new potential therapeutic targets.
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Affiliation(s)
- Xiaoxu Zhou
- Department of Biomedical Engineering, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
| | - Ping Shentu
- Department of Biomedical Engineering, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
| | - Yingke Xu
- Department of Biomedical Engineering, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou 310027, China
- *Yingke Xu:
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20
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Ishida M, E Oguchi M, Fukuda M. Multiple Types of Guanine Nucleotide Exchange Factors (GEFs) for Rab Small GTPases. Cell Struct Funct 2016; 41:61-79. [PMID: 27246931 DOI: 10.1247/csf.16008] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Rab small GTPases are highly conserved master regulators of membrane traffic in all eukaryotes. The same as the activation and inactivation of other small GTPases, the activation and inactivation of Rabs are tightly controlled by specific GEFs (guanine nucleotide exchange factors) and GAPs (GTPase-activating proteins), respectively. Although almost all Rab-GAPs reported thus far have a TBC (Tre-2/Bub2/Cdc16)/Rab-GAP domain in common, recent accumulating evidence has indicated the existence of a number of structurally unrelated types of Rab-GEFs, including DENN proteins, VPS9 proteins, Sec2 proteins, TRAPP complexes, heterodimer GEFs (Mon1-Ccz1, HPS1-HPS4 (BLOC-3 complex), Ric1-Rgp1 and Rab3GAP1/2), and other GEFs (e.g., REI-1 and RPGR). In this review article we provide an up-to-date overview of the structures and functions of all putative Rab-GEFs in mammals, with a special focus on their substrate Rabs, interacting proteins, associations with genetic diseases, and intracellular localizations.
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Affiliation(s)
- Morié Ishida
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University
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21
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Fukuda M. Multiple Roles of VARP in Endosomal Trafficking: Rabs, Retromer Components and R-SNARE VAMP7 Meet on VARP. Traffic 2016; 17:709-19. [PMID: 27103185 DOI: 10.1111/tra.12406] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 12/11/2022]
Abstract
VARP (VPS9-ankyrin-repeat protein, also known as ANKRD27) was originally identified as an N-terminal VPS9 (vacuolar protein sorting 9)-domain-containing protein that possesses guanine nucleotide exchange factor (GEF) activity toward small GTPase Rab21 and contains two ankyrin repeat (ANKR) domains in its central region. A number of VARP-interacting molecules have been identified during the past five years, and considerable attention is now being directed to the multiple roles of VARP in endosomal trafficking. More specifically, VARP is now known to interact with three different types of key membrane trafficking regulators, i.e. small GTPase Rabs (Rab32, Rab38 and Rab40C), the retromer complex (a sorting nexin dimer, VPS26, VPS29 and VPS35) and R-SNARE VAMP7. By binding to several of these molecules, VARP regulates endosomal trafficking, which underlies a variety of cellular events, including melanogenic enzyme trafficking to melanosomes, dendrite outgrowth of melanocytes, neurite outgrowth and retromer-mediated endosome-to-plasma membrane sorting of transmembrane proteins.
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Affiliation(s)
- Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
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22
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Mahurkar S, Moldovan M, Suppiah V, Sorosina M, Clarelli F, Liberatore G, Malhotra S, Montalban X, Antigüedad A, Krupa M, Jokubaitis VG, McKay FC, Gatt PN, Fabis-Pedrini MJ, Martinelli V, Comi G, Lechner-Scott J, Kermode AG, Slee M, Taylor BV, Vandenbroeck K, Comabella M, Boneschi FM, King C. Response to interferon-beta treatment in multiple sclerosis patients: a genome-wide association study. THE PHARMACOGENOMICS JOURNAL 2016; 17:312-318. [PMID: 27001119 DOI: 10.1038/tpj.2016.20] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/04/2015] [Accepted: 02/12/2016] [Indexed: 01/23/2023]
Abstract
Up to 50% of multiple sclerosis (MS) patients do not respond to interferon-beta (IFN-β) treatment and determination of response requires lengthy clinical follow-up of up to 2 years. Response predictive genetic markers would significantly improve disease management. We aimed to identify IFN-β treatment response genetic marker(s) by performing a two-stage genome-wide association study (GWAS). The GWAS was carried out using data from 151 Australian MS patients from the ANZgene/WTCCC2 MS susceptibility GWAS (responder (R)=51, intermediate responders=24 and non-responders (NR)=76). Of the single-nucleotide polymorphisms (SNP) that were validated in an independent group of 479 IFN-β-treated MS patients from Australia, Spain and Italy (R=273 and NR=206), eight showed evidence of association with treatment response. Among the replicated associations, the strongest was observed for FHIT (Fragile Histidine Triad; combined P-value 6.74 × 10-6) and followed by variants in GAPVD1 (GTPase activating protein and VPS9 domains 1; combined P-value 5.83 × 10-5) and near ZNF697 (combined P-value 8.15 × 10-5).
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Affiliation(s)
- S Mahurkar
- School of Pharmacy and Medical Sciences and Sansom Institute for Health Research, University of South Australia, Frome Road, Adelaide, South Australia, Australia
| | - M Moldovan
- South Australian Health &Medical Research Institute and Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia.,Australian Institute of Health Innovation, University of New South Wales, Sydney, Australia
| | - V Suppiah
- School of Pharmacy and Medical Sciences and Sansom Institute for Health Research, University of South Australia, Frome Road, Adelaide, South Australia, Australia
| | - M Sorosina
- Laboratory of Genetics of Complex Neurological Disorders, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - F Clarelli
- Laboratory of Genetics of Complex Neurological Disorders, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - G Liberatore
- Laboratory of Genetics of Complex Neurological Disorders, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology and Neurorehabilitation, San Raffaele Scientific Institute, Milan, Italy
| | - S Malhotra
- Servei de Neurologia-Neuroimmunologia, Centre d'Esclerosi Múltiple de Catalunya (Cemcat), Institut de Receca Vall d'Hebron (VHIR), Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - X Montalban
- Servei de Neurologia-Neuroimmunologia, Centre d'Esclerosi Múltiple de Catalunya (Cemcat), Institut de Receca Vall d'Hebron (VHIR), Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - A Antigüedad
- Servicio de Neurología, Basurto Hospital, Bilbao, Spain
| | - M Krupa
- Flinders University and Medical Centre, Adelaide, South Australia, Australia
| | - V G Jokubaitis
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Victoria, Australia
| | - F C McKay
- Centre for Immunology and Allergy Research, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
| | - P N Gatt
- Centre for Immunology and Allergy Research, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
| | - M J Fabis-Pedrini
- Western Australian Neuroscience Research Institute, Centre for Neuromuscular and Neurological Disorders, University of WA, Nedlands, Western Australia, Australia
| | - V Martinelli
- Laboratory of Genetics of Complex Neurological Disorders, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - G Comi
- Laboratory of Genetics of Complex Neurological Disorders, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology and Neurorehabilitation, San Raffaele Scientific Institute, Milan, Italy
| | - J Lechner-Scott
- Hunter Medical Research Institute, The University of Newcastle, Newcastle, New South Wales, Australia
| | - A G Kermode
- Western Australian Neuroscience Research Institute, Centre for Neuromuscular and Neurological Disorders, University of WA, Nedlands, Western Australia, Australia.,Institute of Immunology and Infectious Diseases, Murdoch University, Western Australia, Australia
| | - M Slee
- Flinders University and Medical Centre, Adelaide, South Australia, Australia
| | - B V Taylor
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | - K Vandenbroeck
- Neurogenomiks Group, Universidad del País Vasco (UPV/EHU), Leioa, Spain.,Achucarro Basque Center for Neuroscience, Zamudio, Spain.,Ikerbasque, Basque Foundation of Science, Bilbao, Spain
| | - M Comabella
- Servei de Neurologia-Neuroimmunologia, Centre d'Esclerosi Múltiple de Catalunya (Cemcat), Institut de Receca Vall d'Hebron (VHIR), Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - F M Boneschi
- Laboratory of Genetics of Complex Neurological Disorders, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology and Neurorehabilitation, San Raffaele Scientific Institute, Milan, Italy
| | | | - C King
- School of Pharmacy and Medical Sciences and Sansom Institute for Health Research, University of South Australia, Frome Road, Adelaide, South Australia, Australia
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23
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Qi Y, Liang Z, Wang Z, Lu G, Li G. Determination of Rab5 activity in the cell by effector pull-down assay. Methods Mol Biol 2016; 1298:259-70. [PMID: 25800849 DOI: 10.1007/978-1-4939-2569-8_22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Rab5 targets to early endosomes and is a master regulator of early endosome fusion and endocytosis in all eukaryotic cells. Like other GTPases, Rab5 functions as a molecular switch by alternating between GTP-bound and GDP-bound forms, with the former being biologically active via interactions with multiple effector proteins. Thus the Rab5-GTP level in the cell reflects Rab5 activity in promoting endosome fusion and endocytosis and is indicative of cellular endocytic activity. In this chapter, we describe a Rab5 activity assay by using GST fusion proteins with the Rab5 effectors such as Rabaptin-5, Rabenosyn-5, and EEA1 that specifically bind to GTP-bound Rab5. We compare the efficiencies of the three GST fusion proteins in the pull-down of mammalian and fungal Rab5 proteins.
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Affiliation(s)
- Yaoyao Qi
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture & Forestry University, 350002, Fuzhou, China
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24
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Carnagarin R, Dharmarajan AM, Dass CR. Molecular aspects of glucose homeostasis in skeletal muscle--A focus on the molecular mechanisms of insulin resistance. Mol Cell Endocrinol 2015; 417:52-62. [PMID: 26362689 DOI: 10.1016/j.mce.2015.09.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 09/02/2015] [Indexed: 01/14/2023]
Abstract
Among all the varied actions of insulin, regulation of glucose homeostasis is the most critical and intensively studied. With the availability of glucose from nutrient metabolism, insulin action in muscle results in increased glucose disposal via uptake from the circulation and storage of excess, thereby maintaining euglycemia. This major action of insulin is executed by redistribution of the glucose transporter protein, GLUT4 from intracellular storage sites to the plasma membrane and storage of glucose in the form of glycogen which also involves modulation of actin dynamics that govern trafficking of all the signal proteins of insulin signal transduction. The cellular mechanisms responsible for these trafficking events and the defects associated with insulin resistance are largely enigmatic, and this review provides a consolidated overview of the various molecular mechanisms involved in insulin-dependent glucose homeostasis in skeletal muscle, as insulin resistance at this major peripheral site impacts whole body glucose homeostasis.
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Affiliation(s)
- Revathy Carnagarin
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia
| | - Arun M Dharmarajan
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Biomedical Science, Curtin University, Bentley 6102, Australia
| | - Crispin R Dass
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia.
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25
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Swetha M, Ramaiah KVA. Insulin treatment promotes tyrosine phosphorylation of PKR and inhibits polyIC induced PKR threonine phosphorylation. Arch Biochem Biophys 2015; 585:98-108. [PMID: 26321373 DOI: 10.1016/j.abb.2015.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 07/18/2015] [Accepted: 07/20/2015] [Indexed: 12/17/2022]
Abstract
Tyrosine phosphorylation of insulin receptor beta (IRβ) in insulin treated HepG2 cells is inversely correlated to ser(51) phosphorylation in the alpha-subunit of eukaryotic initiation factor 2 (eIF2α) that regulates protein synthesis. Insulin stimulates interaction between IRβ and PKR, double stranded RNA-dependent protein kinase, also known as EIF2AK2, and phosphorylation of tyrosine residues in PKR, as analyzed by immunoprecipitation and pull down assays using anti-IRβ and anti-phosphotyrosine antibodies, recombinant IRβ and immunopurified PKR. Further polyIC or synthetic double stranded RNA-induced threonine phosphorylation or activation of immunopurified and cellular PKR is suppressed in the presence of insulin treated purified IRβ and cell extracts. Acute, but not chronic, insulin treatment enhances tyrosine phosphorylation of IRβ, its interaction with PKR and tyrosine phosphorylation of PKR. In contrast, lipopolysaccharide that stimulates threonine phosphorylation of PKR and eIF2α phosphorylation and AG 1024, an inhibitor of the tyrosine kinase activity of IRβ, reduces PKR association with the receptor, IRβ in HepG2 cells. These findings therefore may suggest that tyrosine phosphorylated PKR plays a role in the regulation of insulin induced protein synthesis and in maintaining insulin sensitivity, whereas, suppression of polyIC-mediated threonine phosphorylation of PKR by insulin compromises its ability to fight against virus infection in host cells.
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Affiliation(s)
- Medchalmi Swetha
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500 046, Telangana, India
| | - Kolluru V A Ramaiah
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500 046, Telangana, India.
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26
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Abstract
BAR proteins comprise a heterogeneous group of multi-domain proteins with diverse biological functions. The common denominator is the Bin-Amphiphysin-Rvs (BAR) domain that not only confers targeting to lipid bilayers, but also provides scaffolding to mold lipid membranes into concave or convex surfaces. This function of BAR proteins is an important determinant in the dynamic reconstruction of membrane vesicles, as well as of the plasma membrane. Several BAR proteins function as linkers between cytoskeletal regulation and membrane dynamics. These links are provided by direct interactions between BAR proteins and actin-nucleation-promoting factors of the Wiskott-Aldrich syndrome protein family and the Diaphanous-related formins. The Rho GTPases are key factors for orchestration of this intricate interplay. This review describes how BAR proteins regulate the activity of Rho GTPases, as well as how Rho GTPases regulate the function of BAR proteins. This mutual collaboration is a central factor in the regulation of vital cellular processes, such as cell migration, cytokinesis, intracellular transport, endocytosis, and exocytosis.
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Affiliation(s)
- Pontus Aspenström
- a Department of Microbiology and Tumor and Cell Biology; Karolinska Institutet ; Stockholm , Sweden
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27
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Chua CEL, Tang BL. Role of Rab GTPases and their interacting proteins in mediating metabolic signalling and regulation. Cell Mol Life Sci 2015; 72:2289-304. [PMID: 25690707 PMCID: PMC11113524 DOI: 10.1007/s00018-015-1862-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/09/2015] [Accepted: 02/11/2015] [Indexed: 10/24/2022]
Abstract
The vesicular transport pathways, which shuttle materials to and from the cell surface and within the cell, and the metabolic (growth factor and nutrient) signalling pathways, which integrate a variety of extracellular and intracellular signals to mediate growth, proliferation or survival, are both important for cellular physiology. There is evidence to suggest that the transport and metabolic signalling pathways intersect-vesicular transport can affect the regulation of metabolic signals and vice versa. The Rab family GTPases regulate the specificity of vesicular transport steps in the cell. Together with their interacting proteins, Rabs would likely constitute the points of intersection between vesicular transport and metabolic signalling pathways. Examples of these points would include growth factor signalling, glucose and lipid metabolism, as well as autophagy. Many of these processes involve mechanistic/mammalian target of rapamycin (mTOR) complex 1 (mTORC1) in downstream cascades, or are regulated by TORC signalling. A general functionality of the vesicular transport processes controlled by the Rabs is also important for spatial and temporal regulation of the transmission of metabolic signals between the cell surface and the nucleus. In other cases, specific Rabs and their interacting proteins are known to function in recruiting metabolism-related proteins to target membranes, or may compete with other factors in the TORC signalling pathway as a means of metabolic regulation. We review and discuss herein examples of how Rabs and their interacting proteins can mediate metabolic signalling and regulation in cells.
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Affiliation(s)
- Christelle En Lin Chua
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, 8 Medical Drive, Singapore, 117597, Singapore,
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28
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Yeo JC, Wall AA, Luo L, Stow JL. Rab31 and APPL2 enhance FcγR-mediated phagocytosis through PI3K/Akt signaling in macrophages. Mol Biol Cell 2015; 26:952-65. [PMID: 25568335 PMCID: PMC4342030 DOI: 10.1091/mbc.e14-10-1457] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Rab31 recruits APPL2 to regulate phagocytic cup closure and FcγR signaling pathways via production of PI(3,4,5)P3 in macrophages. APPL2 is poised to activate macrophages and act as a counterpoint to APPL1 in FcγR-mediated PI3K/Akt signaling. New locations and roles are found for Rab31 and APPL2 by which they contribute to innate immune functions. Membrane remodeling in the early stages of phagocytosis enables the engulfment of particles or pathogens and receptor signaling to activate innate immune responses. Members of the Rab GTPase family and their disparate effectors are recruited sequentially to regulate steps throughout phagocytosis. Rab31 (Rab22b) is known for regulating post-Golgi trafficking, and here we show in macrophages that Rab31-GTP is additionally and specifically recruited to early-stage phagosomes. At phagocytic cups, Rab31 is first recruited during the phosphoinositide transition from PI(4,5)P2 to PI(3,4,5)P3, and it persists on PI(3)P-enriched phagosomes. During early phagocytosis, we find that Rab31 recruits the signaling adaptor APPL2. siRNA depletion of either Rab31 or APPL2 reduces FcγR-mediated phagocytosis. Mechanistically, this corresponds with a delay in the transition to PI(3,4,5)P3 and phagocytic cup closure. APPL2 depletion also reduced PI3K/Akt signaling and enhanced p38 signaling from FcγR. We thus conclude that Rab31/APPL2 is required for key roles in phagocytosis and prosurvival responses of macrophages. Of interest, in terms of localization and function, this Rab31/APPL2 complex is distinct from the Rab5/APPL1 complex, which is also involved in phagocytosis and signaling.
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Affiliation(s)
- Jeremy C Yeo
- Institute for Molecular Bioscience, University of Queensland, Brisbane QLD 4072, Australia
| | - Adam A Wall
- Institute for Molecular Bioscience, University of Queensland, Brisbane QLD 4072, Australia
| | - Lin Luo
- Institute for Molecular Bioscience, University of Queensland, Brisbane QLD 4072, Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience, University of Queensland, Brisbane QLD 4072, Australia
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29
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Chua CEL, Tang BL. The role of the small GTPase Rab31 in cancer. J Cell Mol Med 2014; 19:1-10. [PMID: 25472813 PMCID: PMC4288343 DOI: 10.1111/jcmm.12403] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 07/18/2014] [Indexed: 12/28/2022] Open
Abstract
Members of the small GTPase family Rab are emerging as potentially important factors in cancer development and progression. A good number of Rabs have been implicated or associated with various human cancers, and much recent excitement has been associated with the roles of the Rab11 subfamily member Rab25 and its effector, the Rab coupling protein (RCP), in tumourigenesis and metastasis. In this review, we focus on a Rab5 subfamily member, Rab31, and its implicated role in cancer. Well recognized as a breast cancer marker with good prognostic value, recent findings have provided some insights as to the mechanism underlying Rab31's influence on oncogenesis. Levels of Oestrogen Receptor α (ERα)- responsive Rab31 could be elevated through stabilization of its transcript by the RNA binding protein HuR, or though activation by the oncoprotein mucin1-C (MUC1-C), which forms a transcriptional complex with ERα. Elevated Rab31 stabilizes MUC1-C levels in an auto-inductive loop that could lead to aberrant signalling and gene expression associated with cancer progression. Rab31 and its guanine nucleotide exchange factor GAPex-5 have, however, also been shown to enhance early endosome-late endosome transport and degradation of the epidermal growth factor receptor (EGFR). The multifaceted action and influences of Rab31 in cancer is discussed in the light of its new interacting partners and pathways.
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Affiliation(s)
- Christelle En Lin Chua
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
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30
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Govers R. Molecular mechanisms of GLUT4 regulation in adipocytes. DIABETES & METABOLISM 2014; 40:400-10. [DOI: 10.1016/j.diabet.2014.01.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/24/2014] [Accepted: 01/26/2014] [Indexed: 01/28/2023]
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31
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van Dam TJP, Bos JL, Snel B. Evolution of the Ras-like small GTPases and their regulators. Small GTPases 2014; 2:4-16. [PMID: 21686276 DOI: 10.4161/sgtp.2.1.15113] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 02/09/2011] [Accepted: 02/09/2011] [Indexed: 01/28/2023] Open
Abstract
Small GTPases are molecular switches at the hub of many signaling pathways and the expansion of this protein family is interwoven with the origin of unique eukaryotic cell features. We have previously reported on the evolution of CDC25 Homology Domain containing proteins, which act as guanine nucleotide exchange factors (GEFs) for Ras-like proteins. We now report on the evolution of both the Ras-like small GTPases as well as the GTPase activating proteins (GAPs) for Ras-like small GTPases. We performed an in depth phylogenetic analysis in 64 genomes of diverse eukaryotic species. These analyses revealed that multiple ancestral Ras-like GTPases and GAPs were already present in the Last Eukaryotic Common Ancestor (LECA), compatible with the presence of RasGEFs in LECA . Furthermore, we endeavor to reconstruct in which order the different Ras-like GTPases diverged from each other. We identified striking differences between the expansion of the various types of Ras-like GTPases and their respective GAPs and GEFs. Altogether, our analysis forms an extensive evolutionary framework for Ras-like signaling pathways and provides specific predictions for molecular biologists and biochemists.
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Affiliation(s)
- Teunis J P van Dam
- Theoretical Biology and Bioinformatics; Department of Biology; Science Faculty; Utrecht University; Utrecht, The Netherlands
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32
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Satoh T. Molecular mechanisms for the regulation of insulin-stimulated glucose uptake by small guanosine triphosphatases in skeletal muscle and adipocytes. Int J Mol Sci 2014; 15:18677-92. [PMID: 25325535 PMCID: PMC4227239 DOI: 10.3390/ijms151018677] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 09/28/2014] [Accepted: 09/30/2014] [Indexed: 12/11/2022] Open
Abstract
Insulin is a hormone that regulates the blood glucose level by stimulating various physiological responses in its target tissues. In skeletal muscle and adipose tissue, insulin promotes membrane trafficking of the glucose transporter GLUT4 from GLUT4 storage vesicles to the plasma membrane, thereby facilitating the uptake of glucose from the circulation. Detailed mechanisms underlying insulin-dependent intracellular signal transduction for glucose uptake remain largely unknown. In this article, I give an overview on the recently identified signaling network involving Rab, Ras, and Rho family small guanosine triphosphatases (GTPases) that regulates glucose uptake in insulin-responsive tissues. In particular, the regulatory mechanisms for these small GTPases and the cross-talk between protein kinase and small GTPase cascades are highlighted.
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Affiliation(s)
- Takaya Satoh
- Laboratory of Cell Biology, Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
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33
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Luo L, King NP, Yeo JC, Jones A, Stow JL. Single-step protease cleavage elution for identification of protein-protein interactions from GST pull-down and mass spectrometry. Proteomics 2014; 14:19-23. [PMID: 24259493 DOI: 10.1002/pmic.201300315] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/10/2013] [Accepted: 10/28/2013] [Indexed: 11/12/2022]
Abstract
The study of protein-protein interactions is a major theme in biological disciplines. Pull-down or affinity-precipitation assays using GST fusion proteins have become one of the most common and valuable approaches to identify novel binding partners for proteins of interest (bait). Non-specific binding of prey proteins to the beads or to GST itself, however, inevitably complicates and impedes subsequent analysis of pull-down results. A variety of measures, each with inherent advantages and limitations, can minimise the extent of the background. This technical brief details and tests a modification of established GST pull-down protocols. By specifically eluting only the bait (minus the GST tag) and the associated non-specific binding proteins with a simple, single-step protease cleavage, a cleaner platform for downstream protein identification with MS is established. We present a proof of concept for this method, as evidenced by a GST pull-down/MS case study of the small guanosine triphosphatase (GTPase) Rab31 in which: (i) sensitivity was enhanced, (ii) a reduced level of background was observed, (iii) distinguishability of non-specific contaminant proteins from genuine binders was improved and (iv) a putative new protein-protein interaction was discovered. Our protease cleavage step is readily applicable to all further affinity tag pull-downs.
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Affiliation(s)
- Lin Luo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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34
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Karunanithi S, Xiong T, Uhm M, Leto D, Sun J, Chen XW, Saltiel AR. A Rab10:RalA G protein cascade regulates insulin-stimulated glucose uptake in adipocytes. Mol Biol Cell 2014; 25:3059-69. [PMID: 25103239 PMCID: PMC4230594 DOI: 10.1091/mbc.e14-06-1060] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Insulin-stimulated glucose uptake in fat and muscle is mediated by the major facilitative glucose transporter Glut4. Insulin controls the trafficking of Glut4 to the plasma membrane via regulation of a series of small G proteins, including RalA and Rab10. We demonstrate here that Rab10 is a bona fide target of the GTPase-activating protein AS160, which is inhibited after phosphorylation by the protein kinase Akt. Once activated, Rab10 can increase the GTP binding of RalA by recruiting the Ral guanyl nucleotide exchange factor, Rlf/Rgl2. Rab10 and RalA reside in the same pool of Glut4-storage vesicles in untreated cells, and, together with Rlf, they ensure maximal glucose transport. Overexpression of membrane-tethered Rlf compensates for the loss of Rab10 in Glut4 translocation, suggesting that Rab10 recruits Rlf to membrane compartments for RalA activation and that RalA is downstream of Rab10. Together these studies identify a new G protein cascade in the regulation of insulin-stimulated Glut4 trafficking and glucose uptake.
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Affiliation(s)
| | - Tingting Xiong
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI 48109 Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Maeran Uhm
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI 48109 Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Dara Leto
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Jingxia Sun
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Xiao-Wei Chen
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI 48109 Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Alan R Saltiel
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI 48109 Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
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35
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Devanathan S, Whitehead T, Schweitzer GG, Fettig N, Kovacs A, Korach KS, Finck BN, Shoghi KI. An animal model with a cardiomyocyte-specific deletion of estrogen receptor alpha: functional, metabolic, and differential network analysis. PLoS One 2014; 9:e101900. [PMID: 25000186 PMCID: PMC4085004 DOI: 10.1371/journal.pone.0101900] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/12/2014] [Indexed: 12/20/2022] Open
Abstract
Estrogen exerts diverse biological effects in multiple tissues in both animals and humans. Much of the accumulated knowledge on the role of estrogen receptor (ER) in the heart has been obtained from studies using ovariectomized mice, whole body ER gene knock-out animal models, ex vivo heart studies, or from isolated cardiac myocytes. In light of the wide systemic influence of ER signaling in regulating a host of biological functions in multiple tissues, it is difficult to infer the direct role of ER on the heart. Therefore, we developed a mouse model with a cardiomyocyte-specific deletion of the ERα allele (cs-ERα−/−). Male and female cs-ERα−/− mice with age/sex-matched wild type controls were examined for differences in cardiac structure and function by echocardiogram and differential gene expression microarray analysis. Our study revealed sex-differences in structural parameters in the hearts of cs-ERα−/− mice, with minimal functional differences. Analysis of microarray data revealed differential variations in the expression of 208 genes affecting multiple transcriptional networks. Furthermore, we report sex-specific differences in the expression of 56 genes. Overall, we developed a mouse model with cardiac-specific deletion of ERα to characterize the role of ERα in the heart independent of systemic effects. Our results suggest that ERα is involved in controlling the expression of diverse genes and networks in the cardiomyocyte in a sex-dependent manner.
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Affiliation(s)
- Sriram Devanathan
- Department of Radiology, Washington University in St. Louis, Saint Louis, Missouri, United States of America
| | - Timothy Whitehead
- Department of Radiology, Washington University in St. Louis, Saint Louis, Missouri, United States of America
| | - George G. Schweitzer
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University in St. Louis, Saint Louis, Missouri, United States of America
| | - Nicole Fettig
- Department of Radiology, Washington University in St. Louis, Saint Louis, Missouri, United States of America
| | - Attila Kovacs
- Center for Cardiovascular Research, Department of Medicine, Washington University in St. Louis, Saint Louis, Missouri, United States of America
| | - Kenneth S. Korach
- Laboratory of Reproductive and Developmental Toxicology, Receptor Biology Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Brian N. Finck
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University in St. Louis, Saint Louis, Missouri, United States of America
| | - Kooresh I. Shoghi
- Department of Radiology, Washington University in St. Louis, Saint Louis, Missouri, United States of America
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, Missouri, United States of America
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, Saint Louis, Missouri, United States of America
- * E-mail:
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36
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Chua CEL, Tang BL. Engagement of the small GTPase Rab31 protein and its effector, early endosome antigen 1, is important for trafficking of the ligand-bound epidermal growth factor receptor from the early to the late endosome. J Biol Chem 2014; 289:12375-89. [PMID: 24644286 DOI: 10.1074/jbc.m114.548321] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Rab31 is a member of the Rab5 subfamily of Rab GTPases. Although localized largely to the trans-Golgi network, it shares common guanine nucleotide exchange factors and effectors with other Rab5 subfamily members that have been implicated in endocytic membrane traffic. We investigated whether Rab31 also has a role in the trafficking of the ligand-bound EGF receptor (EGFR) internalized through receptor-mediated endocytosis. We found that loss of Rab31 inhibits, but overexpression enhances, EGFR trafficking to the late endosomes and that the effect of Rab31 silencing could be specifically rescued by overexpression of a silencing-resistant form of Rab31. Rab31 was found to interact with the EGFR by coimmunoprecipitation and affinity pulldown analyses, and the primarily trans-Golgi network-localized Rab31 has increased colocalization with the EGFR in A431 cells 30 min after pulsing with EGF. A glycerol gradient sedimentation assay suggested that Rab31 is sequestered into a high molecular weight complex after stimulation with EGF, as was early endosome antigen 1 (EEA1), a factor responsible for endosomal tethering and fusion events. We found that loss of EEA1 reduced the interaction between Rab31 and the EGFR and abrogated the effect of Rab31 overexpression on the trafficking of the EGFR. Likewise, loss of GAPex5, a Rab31 guanine nucleotide exchange factor that has a role in ubiquitination and degradation of the EGFR, reduced the interaction of Rab31 with the EGFR and its effect on EGFR trafficking. Taken together, our results suggest that Rab31 is an important regulator of endocytic trafficking of the EGFR and functions in an EGFR trafficking complex that includes EEA1 and GAPex5.
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Affiliation(s)
- Christelle En Lin Chua
- From the Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, 1E Kent Ridge Road, Singapore 119228 and
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37
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Abstract
Insulin is secreted into blood vessels from β cells of pancreatic islets in response to high blood glucose levels. Insulin stimulates an array of physiological responses in target tissues, including liver, skeletal muscle, and adipose tissue, thereby reducing the blood glucose level. Insulin-dependent glucose uptake in skeletal muscle and adipose tissue is primarily mediated by the redistribution of the glucose transporter type 4 from intracellular storage sites to the plasma membrane. Evidence for the participation of the Rho family GTPase Rac1 in glucose uptake signaling in skeletal muscle has emerged from studies using cell cultures and genetically engineered mice. Herein, recent progress in understanding the function and regulation of Rac1, especially the cross-talk with the protein kinase Akt2, is highlighted. In addition, the role for another Rho family member TC10 and its regulatory mechanism in adipocyte insulin signaling are described.
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Affiliation(s)
- Takaya Satoh
- Laboratory of Cell Biology; Department of Biological Science; Graduate School of Science; Osaka Prefecture University; Osaka, Japan
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38
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Schulze U, Vollenbröker B, Braun DA, Van Le T, Granado D, Kremerskothen J, Fränzel B, Klosowski R, Barth J, Fufezan C, Wolters DA, Pavenstädt H, Weide T. The Vac14-interaction network is linked to regulators of the endolysosomal and autophagic pathway. Mol Cell Proteomics 2014; 13:1397-411. [PMID: 24578385 DOI: 10.1074/mcp.m113.034108] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The scaffold protein Vac14 acts in a complex with the lipid kinase PIKfyve and its counteracting phosphatase FIG4, regulating the interconversion of phosphatidylinositol-3-phosphate to phosphatidylinositol-3,5-bisphosphate. Dysfunctional Vac14 mutants, a deficiency of one of the Vac14 complex components, or inhibition of PIKfyve enzymatic activity results in the formation of large vacuoles in cells. How these vacuoles are generated and which processes are involved are only poorly understood. Here we show that ectopic overexpression of wild-type Vac14 as well as of the PIKfyve-binding deficient Vac14 L156R mutant causes vacuoles. Vac14-dependent vacuoles and PIKfyve inhibitor-dependent vacuoles resulted in elevated levels of late endosomal, lysosomal, and autophagy-associated proteins. However, only late endosomal marker proteins were bound to the membranes of these enlarged vacuoles. In order to decipher the linkage between the Vac14 complex and regulators of the endolysosomal pathway, a protein affinity approach combined with multidimensional protein identification technology was conducted, and novel molecular links were unraveled. We found and verified the interaction of Rab9 and the Rab7 GAP TBC1D15 with Vac14. The identified Rab-related interaction partners support the theory that the regulation of vesicular transport processes and phosphatidylinositol-modifying enzymes are tightly interconnected.
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Affiliation(s)
- Ulf Schulze
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany
| | - Beate Vollenbröker
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany
| | - Daniela A Braun
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany
| | - Truc Van Le
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany
| | - Daniel Granado
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany
| | - Joachim Kremerskothen
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany
| | - Benjamin Fränzel
- ‖Analytical Chemistry NC4/72, Biomolecular Mass Spectrometry/Proteincenter, Ruhr-University Bochum, Universitätsstr. 150, D-44801 Bochum, Germany
| | - Rafael Klosowski
- ‖Analytical Chemistry NC4/72, Biomolecular Mass Spectrometry/Proteincenter, Ruhr-University Bochum, Universitätsstr. 150, D-44801 Bochum, Germany
| | - Johannes Barth
- ‡‡Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 8, D-48143 Muenster, Germany
| | - Christian Fufezan
- ‡‡Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 8, D-48143 Muenster, Germany
| | - Dirk A Wolters
- ‖Analytical Chemistry NC4/72, Biomolecular Mass Spectrometry/Proteincenter, Ruhr-University Bochum, Universitätsstr. 150, D-44801 Bochum, Germany
| | - Hermann Pavenstädt
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany;
| | - Thomas Weide
- From the ‡Department of Internal Medicine D, Molecular Nephrology, University Hospital of Muenster, Albert-Schweitzer Campus 1, A14, D-48149 Muenster, Germany;
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Abstract
GLUT4 is regulated by its intracellular localization. In the absence of insulin, GLUT4 is efficiently retained intracellularly within storage compartments in muscle and fat cells. Upon insulin stimulation (and contraction in muscle), GLUT4 translocates from these compartments to the cell surface where it transports glucose from the extracellular milieu into the cell. Its implication in insulin-regulated glucose uptake makes GLUT4 not only a key player in normal glucose homeostasis but also an important element in insulin resistance and type 2 diabetes. Nevertheless, how GLUT4 is retained intracellularly and how insulin acts on this retention mechanism is largely unclear. In this review, the current knowledge regarding the various molecular processes that govern GLUT4 physiology is discussed as well as the questions that remain.
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40
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Reed SE, Hodgson LR, Song S, May MT, Kelly EE, McCaffrey MW, Mastick CC, Verkade P, Tavaré JM. A role for Rab14 in the endocytic trafficking of GLUT4 in 3T3-L1 adipocytes. J Cell Sci 2013; 126:1931-41. [PMID: 23444368 DOI: 10.1242/jcs.104307] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Insulin enhances the uptake of glucose into adipocytes and muscle cells by promoting the redistribution of the glucose transporter isoform 4 (GLUT4) from intracellular compartments to the cell surface. Rab GTPases regulate the trafficking itinerary of GLUT4 and several have been found on immunopurified GLUT4 vesicles. Specifically, Rab14 has previously been implicated in GLUT4 trafficking in muscle although its role, if any, in adipocytes is poorly understood. Analysis of 3T3-L1 adipocytes using confocal microscopy demonstrated that endogenous GLUT4 and endogenous Rab14 exhibited a partial colocalisation. However, when wild-type Rab14 or a constitutively-active Rab14Q70L mutant were overexpressed in these cells, the colocalisation with both GLUT4 and IRAP became extensive. Interestingly, this colocalisation was restricted to enlarged 'ring-like' vesicular structures (mean diameter 1.3 µm), which were observed in the presence of overexpressed wild-type Rab14 and Rab14Q70L, but not an inactive Rab14S25N mutant. These enlarged vesicles contained markers of early endosomes and were rapidly filled by GLUT4 and transferrin undergoing endocytosis from the plasma membrane. The Rab14Q70L mutant reduced basal and insulin-stimulated cell surface GLUT4 levels, probably by retaining GLUT4 in an insulin-insensitive early endosomal compartment. Furthermore, shRNA-mediated depletion of Rab14 inhibited the transit of GLUT4 through early endosomal compartments towards vesicles and tubules in the perinuclear region. Given the previously reported role of Rab14 in trafficking between endosomes and the Golgi complex, we propose that the primary role of Rab14 in GLUT4 trafficking is to control the transit of internalised GLUT4 from early endosomes into the Golgi complex, rather than direct GLUT4 translocation to the plasma membrane.
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Affiliation(s)
- Sam E Reed
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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41
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Leu YW, Huang THM, Hsiao SH. Epigenetic reprogramming of mesenchymal stem cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 754:195-211. [PMID: 22956503 DOI: 10.1007/978-1-4419-9967-2_10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mesenchymal stem cells (MSCs) are multipotent stem cells of mesodermal origin that can be isolated from various sources and induced into different cell types. Although MSCs possess immune privilege and are more easily obtained than embryonic stem cells, their propensity to tumorigenesis has not been fully explored. Epigenomic changes in DNA methylation and chromatin structure have been hypothesized to be critical in the determination of lineage-specific differentiation and tumorigenesis of MSCs, but this has not been formally proven. We applied a targeted DNA methylation method to methylate a Polycomb group protein-governed gene, Trip10, in MSCs, which accelerated the cell fate determination of MSCs. In addition, targeted methylation of HIC1 and RassF1A, both tumor suppressor genes, transformed MSCs into tumor stem cell-like cells. This new method will allow better control of the differentiation of MSCs and their use in downstream applications.
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Affiliation(s)
- Yu-Wei Leu
- Department of Life Science, National Chung Cheng University, Chia-Yi 621, Taiwan.
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42
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King GJ, Stöckli J, Hu SH, Winnen B, Duprez WGA, Meoli CC, Junutula JR, Jarrott RJ, James DE, Whitten AE, Martin JL. Membrane curvature protein exhibits interdomain flexibility and binds a small GTPase. J Biol Chem 2012; 287:40996-1006. [PMID: 23055524 DOI: 10.1074/jbc.m112.349803] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The APPL1 and APPL2 proteins (APPL (adaptor protein, phosphotyrosine interaction, pleckstrin homology (PH) domain, and leucine zipper-containing protein)) are localized to their own endosomal subcompartment and interact with a wide range of proteins and small molecules at the cell surface and in the nucleus. They play important roles in signal transduction through their ability to act as Rab effectors. (Rabs are a family of Ras GTPases involved in membrane trafficking.) Both APPL1 and APPL2 comprise an N-terminal membrane-curving BAR (Bin-amphiphysin-Rvs) domain linked to a PH domain and a C-terminal phosphotyrosine-binding domain. The structure and interactions of APPL1 are well characterized, but little is known about APPL2. Here, we report the crystal structure and low resolution solution structure of the BARPH domains of APPL2. We identify a previously undetected hinge site for rotation between the two domains and speculate that this motion may regulate APPL2 functions. We also identified Rab binding partners of APPL2 and show that these differ from those of APPL1, suggesting that APPL-Rab interaction partners have co-evolved over time. Isothermal titration calorimetry data reveal the interaction between APPL2 and Rab31 has a K(d) of 140 nM. Together with other biophysical data, we conclude the stoichiometry of the complex is 2:2.
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Affiliation(s)
- Gordon J King
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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43
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Grismayer B, Sölch S, Seubert B, Kirchner T, Schäfer S, Baretton G, Schmitt M, Luther T, Krüger A, Kotzsch M, Magdolen V. Rab31 expression levels modulate tumor-relevant characteristics of breast cancer cells. Mol Cancer 2012; 11:62. [PMID: 22920728 PMCID: PMC3499445 DOI: 10.1186/1476-4598-11-62] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 08/16/2012] [Indexed: 11/12/2022] Open
Abstract
Background Rab proteins constitute a large family of monomeric GTP-binding proteins that regulate intracellular vesicle transport. Several Rab proteins, including rab31, have been shown to affect cancer progression and are related with prognosis in various types of cancer including breast cancer. Recently, the gene encoding rab31 was found to be overexpressed in estrogen receptor-positive breast cancer tissue. In a previous study we found a significant association of high rab31 mRNA expression with poor prognosis in node-negative breast cancer patients. In the present study, we aimed to investigate the impact of rab31 (over)-expression on important aspects of tumor progression in vitro and in vivo. Methods Breast cancer cells displaying low (MDA-MB-231) or no (CAMA-1) endogenous rab31 expression were stably transfected with a rab31 expression plasmid. Batch-transfected cells as well as selected cell clones, expressing different levels of rab31 protein, were analyzed with regard to proliferation, cell adhesion, the invasive capacity of tumor cells, and in vivo in a xenograft tumor model. Polyclonal antibodies directed to recombinantly expressed rab31 were generated and protein expression analyzed by immunohistochemistry, Western blot analysis, and a newly developed sensitive ELISA. Results Elevated rab31 protein levels were associated with enhanced proliferation of breast cancer cells. Interestingly, weak to moderate overexpression of rab31 in cell lines with no detectable endogenous rab31 expression was already sufficient to elicit distinct effects on cell proliferation. By contrast, increased expression of rab31 in breast cancer cells led to reduced adhesion towards several extracellular matrix proteins and decreased invasive capacity through MatrigelTM. Again, the rab31-mediated effects on cell adhesion and invasion were dose-dependent. Finally, in a xenograft mouse model, we observed a significantly impaired metastatic dissemination of rab31 overexpressing MDA-MB-231 breast cancer cells to the lung. Conclusions Overexpression of rab31 in breast cancer cells leads to a switch from an invasive to a proliferative phenotype as indicated by an increased cell proliferation, reduced adhesion and invasion in vitro, and a reduced capacity to form lung metastases in vivo.
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Affiliation(s)
- Bettina Grismayer
- Clinical Research Unit, Department of Obstetrics and Gynecology, Technical University of Munich, Ismaninger Str, 22, Munich 81675, Germany
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44
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Bridges D, Chang L, Lodhi IJ, Clark NA, Saltiel AR. TC10 is regulated by caveolin in 3T3-L1 adipocytes. PLoS One 2012; 7:e42451. [PMID: 22900022 PMCID: PMC3416860 DOI: 10.1371/journal.pone.0042451] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 07/05/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND TC10 is a small GTPase found in lipid raft microdomains of adipocytes. The protein undergoes activation in response to insulin, and plays a key role in the regulation of glucose uptake by the hormone. METHODOLOGY/PRINCIPAL FINDINGS TC10 requires high concentrations of magnesium in order to stabilize guanine nucleotide binding. Kinetic analysis of this process revealed that magnesium acutely decreased the nucleotide release and exchange rates of TC10, suggesting that the G protein may behave as a rapidly exchanging, and therefore active protein in vivo. However, in adipocytes, the activity of TC10 is not constitutive, indicating that mechanisms must exist to maintain the G protein in a low activity state in untreated cells. Thus, we searched for proteins that might bind to and stabilize TC10 in the inactive state. We found that Caveolin interacts with TC10 only when GDP-bound and stabilizes GDP binding. Moreover, knockdown of Caveolin 1 in 3T3-L1 adipocytes increased the basal activity state of TC10. CONCLUSIONS/SIGNIFICANCE Together these data suggest that TC10 is intrinsically active in vivo, but is maintained in the inactive state by binding to Caveolin 1 in 3T3-L1 adipocytes under basal conditions, permitting its activation by insulin.
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Affiliation(s)
- Dave Bridges
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Louise Chang
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Irfan J. Lodhi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Natalie A. Clark
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Alan R. Saltiel
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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45
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Lodhi IJ, Yin L, Jensen-Urstad APL, Funai K, Coleman T, Baird JH, El Ramahi MK, Razani B, Song H, Fu-Hsu F, Turk J, Semenkovich CF. Inhibiting adipose tissue lipogenesis reprograms thermogenesis and PPARγ activation to decrease diet-induced obesity. Cell Metab 2012; 16:189-201. [PMID: 22863804 PMCID: PMC3467338 DOI: 10.1016/j.cmet.2012.06.013] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 03/07/2012] [Accepted: 06/22/2012] [Indexed: 10/28/2022]
Abstract
De novo lipogenesis in adipocytes, especially with high fat feeding, is poorly understood. We demonstrate that an adipocyte lipogenic pathway encompassing fatty acid synthase (FAS) and PexRAP (peroxisomal reductase activating PPARγ) modulates endogenous PPARγ activation and adiposity. Mice lacking FAS in adult adipose tissue manifested increased energy expenditure, increased brown fat-like adipocytes in subcutaneous adipose tissue, and resistance to diet-induced obesity. FAS knockdown in embryonic fibroblasts decreased PPARγ transcriptional activity and adipogenesis. FAS-dependent alkyl ether phosphatidylcholine species were associated with PPARγ and treatment of 3T3-L1 cells with one such ether lipid increased PPARγ transcriptional activity. PexRAP, a protein required for alkyl ether lipid synthesis, was associated with peroxisomes and induced during adipogenesis. PexRAP knockdown in cells decreased PPARγ transcriptional activity and adipogenesis. PexRAP knockdown in mice decreased expression of PPARγ-dependent genes and reduced diet-induced adiposity. These findings suggest that inhibiting PexRAP or related lipogenic enzymes could treat obesity and diabetes.
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Affiliation(s)
- Irfan J Lodhi
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA
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46
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Jin C, Rajabi H, Pitroda S, Li A, Kharbanda A, Weichselbaum R, Kufe D. Cooperative interaction between the MUC1-C oncoprotein and the Rab31 GTPase in estrogen receptor-positive breast cancer cells. PLoS One 2012; 7:e39432. [PMID: 22792175 PMCID: PMC3392244 DOI: 10.1371/journal.pone.0039432] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/21/2012] [Indexed: 01/12/2023] Open
Abstract
Rab31 is a member of the Ras superfamily of small GTPases that has been linked to poor outcomes in patients with breast cancer. The MUC1-C oncoprotein is aberrantly overexpressed in most human breast cancers and also confers a poor prognosis. The present results demonstrate that MUC1-C induces Rab31 expression in estrogen receptor positive (ER+) breast cancer cells. We show that MUC1-C forms a complex with estrogen receptor α (ERα) on the Rab31 promoter and activates Rab31 gene transcription in an estrogen-dependent manner. In turn, Rab31 contributes to the upregulation of MUC1-C abundance in breast cancer cells by attenuating degradation of MUC1-C in lysosomes. Expression of an inactive Rab31(S20N) mutant in nonmalignant breast epithelial cells confirmed that Rab31 regulates MUC1-C expression. The functional significance of the MUC1-C/Rab31 interaction is supported by the demonstration that Rab31 confers the formation of mammospheres by a MUC1-C-dependent mechanism. Analysis of microarray databases further showed that (i) Rab31 is expressed at higher levels in breast cancers as compared to that in normal breast tissues, (ii) MUC1+ and ER+ breast cancers have increased levels of Rab31 expression, and (iii) patients with Rab31-positive breast tumors have a significantly decreased ten-year overall survival as compared to those with Rab31-negative tumors. These findings indicate that MUC1-C and Rab31 function in an autoinductive loop that contributes to overexpression of MUC1-C in breast cancer cells.
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Affiliation(s)
- Caining Jin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hasan Rajabi
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sean Pitroda
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois, United States of America
| | - Ailing Li
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Akriti Kharbanda
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ralph Weichselbaum
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois, United States of America
| | - Donald Kufe
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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47
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Abstract
GLUT4 is an insulin-regulated glucose transporter that is responsible for insulin-regulated glucose uptake into fat and muscle cells. In the absence of insulin, GLUT4 is mainly found in intracellular vesicles referred to as GLUT4 storage vesicles (GSVs). Here, we summarise evidence for the existence of these specific vesicles, how they are sequestered inside the cell and how they undergo exocytosis in the presence of insulin. In response to insulin stimulation, GSVs fuse with the plasma membrane in a rapid burst and in the continued presence of insulin GLUT4 molecules are internalised and recycled back to the plasma membrane in vesicles that are distinct from GSVs and probably of endosomal origin. In this Commentary we discuss evidence that this delivery process is tightly regulated and involves numerous molecules. Key components include the actin cytoskeleton, myosin motors, several Rab GTPases, the exocyst, SNARE proteins and SNARE regulators. Each step in this process is carefully orchestrated in a sequential and coupled manner and we are beginning to dissect key nodes within this network that determine vesicle-membrane fusion in response to insulin. This regulatory process clearly involves the Ser/Thr kinase AKT and the exquisite manner in which this single metabolic process is regulated makes it a likely target for lesions that might contribute to metabolic disease.
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Affiliation(s)
- Jacqueline Stöckli
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia
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48
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Bridges D, Fisher K, Zolov SN, Xiong T, Inoki K, Weisman LS, Saltiel AR. Rab5 proteins regulate activation and localization of target of rapamycin complex 1. J Biol Chem 2012; 287:20913-21. [PMID: 22547071 PMCID: PMC3375515 DOI: 10.1074/jbc.m111.334060] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) complex 1 is regulated by small GTPase activators and localization signals. We examine here the role of the small GTPase Rab5 in the localization and activation of TORC1 in yeast and mammalian cells. Rab5 mutants disrupt mTORC1 activation and localization in mammalian cells, whereas disruption of the Rab5 homolog in yeast, Vps21, leads to decreased TORC1 function. Additionally, regulation of PI(3)P synthesis by Rab5 and Vps21 is essential for TORC1 function in both contexts.
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Affiliation(s)
| | | | | | - Tingting Xiong
- From the Life Sciences Institute and ,Molecular and Integrative Physiology, and
| | - Ken Inoki
- From the Life Sciences Institute and ,Molecular and Integrative Physiology, and
| | - Lois S. Weisman
- From the Life Sciences Institute and ,Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Alan R. Saltiel
- From the Life Sciences Institute and ,Departments of Internal Medicine, ,Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, To whom correspondence should be addressed: Life Sciences Institute, University of Michigan, 210 Washtenaw Ave., Ann Arbor, MI 48109. Tel.: 734-615-9787; Fax: 734-763-6492; E-mail:
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49
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Jean S, Cox S, Schmidt EJ, Robinson FL, Kiger A. Sbf/MTMR13 coordinates PI(3)P and Rab21 regulation in endocytic control of cellular remodeling. Mol Biol Cell 2012; 23:2723-40. [PMID: 22648168 PMCID: PMC3395661 DOI: 10.1091/mbc.e12-05-0375] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The MTM phosphatases include poorly defined, catalytically inactive members. Drosophila Sbf, an MTM pseudophosphatase, physically and functionally interacts with class II PI3-kinase, Mtm PI3-phosphatase, and Rab21, each required for macrophage remodeling. Sbf plays dual roles in Mtm PI(3)P turnover and as a Rab21 GEF to coordinate endosomal dynamics. Cells rely on the coordinated regulation of lipid phosphoinositides and Rab GTPases to define membrane compartment fates along distinct trafficking routes. The family of disease-related myotubularin (MTM) phosphoinositide phosphatases includes catalytically inactive members, or pseudophosphatases, with poorly understood functions. We found that Drosophila MTM pseudophosphatase Sbf coordinates both phosphatidylinositol 3-phosphate (PI(3)P) turnover and Rab21 GTPase activation in an endosomal pathway that controls macrophage remodeling. Sbf dynamically interacts with class II phosphatidylinositol 3-kinase and stably recruits Mtm to promote turnover of a PI(3)P subpool essential for endosomal trafficking. Sbf also functions as a guanine nucleotide exchange factor that promotes Rab21 GTPase activation associated with PI(3)P endosomes. Of importance, Sbf, Mtm, and Rab21 function together, along with Rab11-mediated endosomal trafficking, to control macrophage protrusion formation. This identifies Sbf as a critical coordinator of PI(3)P and Rab21 regulation, which specifies an endosomal pathway and cortical control.
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Affiliation(s)
- Steve Jean
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0380, USA
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50
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Abstract
Despite daily fasting and feeding, plasma glucose levels are normally maintained within a narrow range owing to the hormones insulin and glucagon. Insulin increases glucose uptake into fat and muscle cells through the regulated trafficking of vesicles that contain glucose transporter type 4 (GLUT4). New insights into insulin signalling reveal that phosphorylation events initiated by the insulin receptor regulate key GLUT4 trafficking proteins, including small GTPases, tethering complexes and the vesicle fusion machinery. These proteins, in turn, control GLUT4 movement through the endosomal system, formation and retention of specialized GLUT4 storage vesicles and targeted exocytosis of these vesicles. Understanding these processes may help to explain the development of insulin resistance in type 2 diabetes and provide new potential therapeutic targets.
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