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Lei Z, Wang J, Zhang L, Liu CH. Ubiquitination-Dependent Regulation of Small GTPases in Membrane Trafficking: From Cell Biology to Human Diseases. Front Cell Dev Biol 2021; 9:688352. [PMID: 34277632 PMCID: PMC8281112 DOI: 10.3389/fcell.2021.688352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/09/2021] [Indexed: 01/04/2023] Open
Abstract
Membrane trafficking is critical for cellular homeostasis, which is mainly carried out by small GTPases, a class of proteins functioning in vesicle budding, transport, tethering and fusion processes. The accurate and organized membrane trafficking relies on the proper regulation of small GTPases, which involves the conversion between GTP- and GDP-bound small GTPases mediated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Emerging evidence indicates that post-translational modifications (PTMs) of small GTPases, especially ubiquitination, play an important role in the spatio-temporal regulation of small GTPases, and the dysregulation of small GTPase ubiquitination can result in multiple human diseases. In this review, we introduce small GTPases-mediated membrane trafficking pathways and the biological processes of ubiquitination-dependent regulation of small GTPases, including the regulation of small GTPase stability, activity and localization. We then discuss the dysregulation of small GTPase ubiquitination and the associated human membrane trafficking-related diseases, focusing on the neurological diseases and infections. An in-depth understanding of the molecular mechanisms by which ubiquitination regulates small GTPases can provide novel insights into the membrane trafficking process, which knowledge is valuable for the development of more effective and specific therapeutics for membrane trafficking-related human diseases.
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Affiliation(s)
- Zehui Lei
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Cui Hua Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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2
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Zhang J, Zhao X, Luan Z, Wang A. Rab14 Overexpression Promotes Proliferation and Invasion Through YAP Signaling in Non-Small Cell Lung Cancers. Onco Targets Ther 2020; 13:9269-9280. [PMID: 32982313 PMCID: PMC7509480 DOI: 10.2147/ott.s255644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 07/20/2020] [Indexed: 01/02/2023] Open
Abstract
Introduction Several reports have shown that Rab14 is dysregulated in human cancers suggesting that it is an oncogenic protein closely related to tumorigenesis. However, whether Rab14 plays a role in the development and progression of human non-small cell lung cancer (NSCLC) remains unclear. Methods Rab14 protein levels were examined in 115 cases of NSCLC tissues and 6 cancer cell lines. Rab14 knockdown was performed in H1299 and A549 cell lines. Rab14 plasmid transfection was performed in the LK2 cell line. The biological roles and mechanisms of Rab14 were examined using MTT, colony formation, Matrigel invasion assay, migration assay, cell cycle analysis, Western blotting, and RT-qPCR. Results We found that Rab14 was upregulated in 65 of 115 lung cancer tissues. Rab14 high expression was significantly correlated with advanced TNM stage and nodal metastasis. Rab14 protein levels were higher in lung cancer cell lines than in normal bronchial cell line. Functionally, Rab14 overexpression increased growth rate, colony formation, invasion/migration ability and cell cycle progression, while Rab14 siRNA decreased the cell proliferation rate, colony numbers and inhibited invasion/migration ability and cell cycle progression. Rab14 upregulated cyclin D1, cyclin E, connective tissue growth factor (CTGF) and downregulated p27 protein and mRNA levels in both A549 and H1299 cell lines, while Rab14 siRNA produced the opposite effects. Further study showed that Rab14 overexpression increased luciferase reporter activity from transcriptional enhanced associate domain (TEAD) protein. Accordingly, Rab14 increased total Yes-associated protein (YAP) and nuclear YAP protein while decreased phosphorylated (p)-YAP and cytoplasmic YAP protein expression. Cycloheximide treatment showed that Rab14 downregulated the level of YAP degradation. Depletion of YAP using siRNA abolished the influence of Rab14 on cyclin D1, cyclin E, and CTGF. YAP knockdown also partly abolished the effects of Rab14 on cell proliferation and invasion. Conclusion In summary, our data showed that Rab14 is overexpressed in human NSCLC. Rab14 facilitated proliferation and invasion, possibly through regulation of YAP signaling.
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Affiliation(s)
- Jun Zhang
- Clinical Nursing Section, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Xinyang Zhao
- Department of Respiratory Medicine, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Zhenggang Luan
- Department of Intensive Care Unit, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Aiping Wang
- Clinical Nursing Section, The First Hospital of China Medical University, Shenyang, People's Republic of China
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Groener M, Wang Y, Cross E, Tian X, Ebenezer K, Baik E, Pedigo C, Schiffer M, Inoue K, Ishibe S. Identification of Podocyte Cargo Proteins by Proteomic Analysis of Clathrin-Coated Vesicles. KIDNEY360 2020; 1:480-490. [PMID: 35368594 PMCID: PMC8809311 DOI: 10.34067/kid.0000212020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/13/2020] [Indexed: 04/20/2023]
Abstract
Background Clathrin-mediated endocytosis (CME) plays a fundamental role in podocyte health. Genetic ablation of genes implicated in CME has been shown to cause severe proteinuria and foot process effacement in mice. However, little is known about the cargo of clathrin-coated vesicles (CCVs) in podocytes. The goal of this study was to isolate CCVs from podocytes and identify their cargo by proteomic analysis. Methods Glomeruli isolated from Podocin-Cre Rosa-DTRflox mouse kidneys were seeded and treated with diphtheria toxin to obtain pure primary podocyte cultures. CCVs were isolated by differential gradient ultracentrifugation, and enrichment of CCVs was assessed by immunoblotting and electron microscopy (EM). Liquid chromatography-mass spectrometry (LC-MS) was performed for proteomic analysis. Proteins with higher abundance than transferrin receptor protein 1 were evaluated for CCV cargo potential against previously published literature. Immunofluorescence staining of identified cargo proteins and CCVs was performed in podocytes for further verification. Results Immunoblotting for multiple protein markers of CME revealed enrichment in the CCV fraction. Enrichment of CCVs among other small vesicles was observed via EM. Proteomics yielded a total of >1200 significant proteins. Multiple-step data analysis revealed 36 CCV-associated proteins, of which 10 represent novel, highly abundant cargo proteins in podocytes. Colocalization of cargo proteins and CCVs on immunostaining was observed. Conclusions Our identification of podocyte CCV cargo proteins helps to elucidate the importance of endocytic trafficking for podocyte health and maintenance of the glomerular environment.
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Affiliation(s)
- Marwin Groener
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ying Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Elizabeth Cross
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Xuefei Tian
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Karen Ebenezer
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Eunice Baik
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Christopher Pedigo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Mario Schiffer
- Department of Nephrology and Hypertension, University Hospital Erlangen, Erlangen, Germany
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- Mount Desert Island Biological Laboratories, Salisbury Cove, Maine
| | - Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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4
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Xiao L, Liu D, Zuo S, Zhu X, Wang Y, Dong C. Urea-modulated UT-B urea transporter internalization is clathrin- and caveolae-dependent in infantile hemangioma-derived vascular endothelial cells. J Cell Biochem 2019; 120:5128-5136. [PMID: 30367514 DOI: 10.1002/jcb.27789] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/10/2018] [Indexed: 11/10/2022]
Abstract
The aim of this study was to investigate the manner of urea-modulated UT-B urea transporter (UT) internalization in infantile hemangioma-derived vascular endothelial cells (HemECs). The immunohistochemistry assay was performed to identify infancy hemangioma-derived endothelial cell line (XPTS-1) cells. Cell toxicity was detected with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. Quantitative real-time polymerase chain reaction and Western blot analysis were measured to analyze the expression of UT-B. UT-B internalization was observed by confocal microscopy. The clathrin inhibitor chlorpromazine (CPZ) and caveolin endocytic disrupter methyl-β-cyclodextrin (MβCD) were used in XPTS-1 cells transfected with UT-B-GFP to repress endocytosis. Urea-promoted UT-B expression in a concentration-dependent manner in an infantile XPTS-1 cell line. CPZ and MβCD significantly inhibited UT-B protein internalization. The pretreatment of UT-B-GFP cells with adaptor protein2 (AP2)-μ2-siRNA and caveolin-siRNA significantly inhibited UT-B protein internalization. Our findings suggested that urea-mediated UT-B UT internalization is clathrin and caveolae dependent in infantile HemECs.
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Affiliation(s)
- Li Xiao
- Department of Hemangioma, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Dakan Liu
- Department of Hemangioma, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Song Zuo
- Department of Hemangioma, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Xiaoshuang Zhu
- Department of Hemangioma, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Yanlin Wang
- Department of Hemangioma, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Changxian Dong
- Department of Hemangioma, Henan Provincial People's Hospital, Zhengzhou, Henan, China
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Seixas E, Escrevente C, Seabra MC, Barral DC. Rab GTPase regulation of bacteria and protozoa phagocytosis occurs through the modulation of phagocytic receptor surface expression. Sci Rep 2018; 8:12998. [PMID: 30158654 PMCID: PMC6115379 DOI: 10.1038/s41598-018-31171-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 08/08/2018] [Indexed: 01/22/2023] Open
Abstract
Phagocytosis of invading microorganisms by professional phagocytic cells has a central role in innate immunity. However, several microorganisms developed strategies to subvert this process. Previously, we reported that bacteria and protozoa modulate differently the expression of Rab GTPases. Moreover, our results suggested that this modulation can contribute to avoid phagocytosis. Here, we investigated the mechanism by which the malaria parasite Plasmodium berghei and the bacterium Escherichia coli subvert phagocytosis through the modulation of Rab14 or Rab9a expression, respectively. We first confirmed that the scavenger receptor CD36 and the Toll-like receptor (TLR) 4 are required for the phagocytosis of P. berghei and E. coli, respectively. Interestingly, we observed that Rab14 silencing leads to an increase in the surface expression of CD36 in macrophages, which can explain the increase in the phagocytosis of P. berghei we reported previously. Similar results were obtained for Rab9a and TLR4, i.e. Rab9a silencing causes an upregulation of TLR4 surface expression in macrophages. Furthermore, we found that the decrease in the internalization of CD36 and TLR4, upon Rab14 or Rab9a silencing, respectively, can explain the increase in the surface levels of these receptors. Thus, our studies provide evidence that the modulation of phagocytosis caused by changes in Rab expression is operated, at least partly through changes in the surface levels of phagocytic receptors.
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Affiliation(s)
- Elsa Seixas
- Centro de Estudos de Doenças Crónicas, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal.,Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Cristina Escrevente
- Centro de Estudos de Doenças Crónicas, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Miguel C Seabra
- Centro de Estudos de Doenças Crónicas, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Duarte C Barral
- Centro de Estudos de Doenças Crónicas, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal.
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Chou CL, Hwang G, Hageman DJ, Han L, Agrawal P, Pisitkun T, Knepper MA. Identification of UT-A1- and AQP2-interacting proteins in rat inner medullary collecting duct. Am J Physiol Cell Physiol 2018; 314:C99-C117. [PMID: 29046292 PMCID: PMC5866378 DOI: 10.1152/ajpcell.00082.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 11/22/2022]
Abstract
The urea channel UT-A1 and the water channel aquaporin-2 (AQP2) mediate vasopressin-regulated transport in the renal inner medullary collecting duct (IMCD). To identify the proteins that interact with UT-A1 and AQP2 in native rat IMCD cells, we carried out chemical cross-linking followed by detergent solubilization, immunoprecipitation, and LC-MS/MS analysis of the immunoprecipitated material. The analyses revealed 133 UT-A1-interacting proteins and 139 AQP2-interacting proteins, each identified in multiple replicates. Fifty-three proteins that were present in both the UT-A1 and the AQP2 interactomes can be considered as mediators of housekeeping interactions, likely common to all plasma membrane proteins. Among proteins unique to the UT-A1 list were those involved in posttranslational modifications: phosphorylation (protein kinases Cdc42bpb, Phkb, Camk2d, and Mtor), ubiquitylation/deubiquitylation (Uba1, Usp9x), and neddylation (Nae1 and Uba3). Among the proteins unique to the AQP2 list were several Rab proteins (Rab1a, Rab2a, Rab5b, Rab5c, Rab7a, Rab11a, Rab11b, Rab14, Rab17) involved in membrane trafficking. UT-A1 was found to interact with UT-A3, although quantitative proteomics revealed that most UT-A1 molecules in the cell are not bound to UT-A3. In vitro incubation of UT-A1 peptides with the protein kinases identified in the UT-A1 interactome revealed that all except Mtor were capable of phosphorylating known sites in UT-A1. Overall, the UT-A1 and AQP2 interactomes provide a snapshot of a dynamic process in which UT-A1 and AQP2 are produced in the rough endoplasmic reticulum, processed through the Golgi apparatus, delivered to endosomes that move into and out of the plasma membrane, and are regulated in the plasma membrane.
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Affiliation(s)
- Chung-Lin Chou
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Gloria Hwang
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Daniel J Hageman
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Lichy Han
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Prashasti Agrawal
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Trairak Pisitkun
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
- Faculty of Medicine, Chulalongkorn University , Bangkok , Thailand
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
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Abstract
Cells lining the proximal tubule (PT) of the kidney are highly specialized for apical endocytosis of filtered proteins and small bioactive molecules from the glomerular ultrafiltrate to maintain essentially protein-free urine. Compromise of this pathway results in low molecular weight (LMW) proteinuria that can progress to end-stage kidney disease. This review describes our current understanding of the endocytic pathway and the multiligand receptors that mediate LMW protein uptake in PT cells, how these are regulated in response to physiologic cues, and the molecular basis of inherited diseases characterized by LMW proteinuria.
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Affiliation(s)
- Megan L Eshbach
- Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261; ,
| | - Ora A Weisz
- Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261; ,
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8
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Chawla A, Alatrash G, Philips AV, Qiao N, Sukhumalchandra P, Kerros C, Diaconu I, Gall V, Neal S, Peters HL, Clise-Dwyer K, Molldrem JJ, Mittendorf EA. Neutrophil elastase enhances antigen presentation by upregulating human leukocyte antigen class I expression on tumor cells. Cancer Immunol Immunother 2016; 65:741-51. [PMID: 27129972 PMCID: PMC5764112 DOI: 10.1007/s00262-016-1841-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 04/09/2016] [Indexed: 12/24/2022]
Abstract
Neutrophil elastase (NE) is an innate immune cell-derived inflammatory mediator that we have shown increases the presentation of tumor-associated peptide antigens in breast cancer. In this study, we extend these observations to show that NE uptake has a broad effect on enhancing antigen presentation by breast cancer cells. We show that NE increases human leukocyte antigen (HLA) class I expression on the surface of breast cancer cells in a concentration and time-dependent manner. HLA class I upregulation requires internalization of enzymatically active NE. Western blots of NE-treated breast cancer cells confirm that the expression of total HLA class I as well as the antigen-processing machinery proteins TAP1, LMP2, and calnexin does not change following NE treatment. This suggests that NE does not increase the efficiency of antigen processing; rather, it mediates the upregulation of HLA class I by stabilizing and reducing membrane recycling of HLA class I molecules. Furthermore, the effects of NE extend beyond breast cancer since the uptake of NE by EBV-LCL increases the presentation of HLA class I-restricted viral peptides, as shown by their increased sensitivity to lysis by EBV-specific CD8+ T cells. Together, our results show that NE uptake increases the responsiveness of breast cancer cells to adaptive immunity by broad upregulation of membrane HLA class I and support the conclusion that the innate inflammatory mediator NE enhances tumor cell recognition and increases tumor sensitivity to the host adaptive immune response.
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Affiliation(s)
- Akhil Chawla
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Gheath Alatrash
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 0900, Houston, TX, 77030, USA.
| | - Anne V Philips
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Na Qiao
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Pariya Sukhumalchandra
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 0900, Houston, TX, 77030, USA
| | - Celine Kerros
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 0900, Houston, TX, 77030, USA
| | - Iulia Diaconu
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, USA
| | - Victor Gall
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Samantha Neal
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Haley L Peters
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 0900, Houston, TX, 77030, USA
| | - Karen Clise-Dwyer
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 0900, Houston, TX, 77030, USA
| | - Jeffrey J Molldrem
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 0900, Houston, TX, 77030, USA
| | - Elizabeth A Mittendorf
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Department of Breast Surgical Oncology, The University of Texas MD Anderson Cancer Center, 1400 Pressler Street, Unit 1434, Houston, TX, 77030, USA.
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9
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Feng X, Li Z, Du Y, Fu H, Klein JD, Cai H, Sands JM, Chen G. Downregulation of urea transporter UT-A1 activity by 14-3-3 protein. Am J Physiol Renal Physiol 2015; 309:F71-8. [PMID: 25995111 PMCID: PMC4490382 DOI: 10.1152/ajprenal.00546.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 05/13/2015] [Indexed: 11/22/2022] Open
Abstract
Urea transporter (UT)-A1 in the kidney inner medulla plays a critical role in the urinary concentrating mechanism and thereby in the regulation of water balance. The 14-3-3 proteins are a family of seven isoforms. They are multifunctional regulatory proteins that mainly bind to phosphorylated serine/threonine residues in target proteins. In the present study, we found that all seven 14-3-3 isoforms were detected in the kidney inner medulla. However, only the 14-3-3 γ-isoform was specifically and highly associated with UT-A1, as demonstrated by a glutathione-S-transferase-14-3-3 pulldown assay. The cAMP/adenylyl cyclase stimulator forskolin significantly enhanced their binding. Coinjection of 14-3-3γ cRNA into oocytes resulted in a decrease of UT-A1 function. In addition, 14-3-3γ increased UT-A1 ubiquitination and protein degradation. 14-3-3γ can interact with both UT-A1 and mouse double minute 2, the E3 ubiquitin ligase for UT-A1. Thus, activation of cAMP/PKA increases 14-3-3γ interactions with UT-A1 and stimulates mouse double minute 2-mediated UT-A1 ubiquitination and degradation, thereby forming a novel regulatory mechanism of urea transport activity.
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Affiliation(s)
- Xiuyan Feng
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Section of Nephrology, Atlanta Veterans Administration Medical Center, Decatur, Georgia
| | - Zenggang Li
- Department of Pharmacology, Emory University, School of Medicine, Atlanta, Georgia
| | - Yuhong Du
- Department of Pharmacology, Emory University, School of Medicine, Atlanta, Georgia
| | - Haian Fu
- Department of Pharmacology, Emory University, School of Medicine, Atlanta, Georgia
| | - Janet D Klein
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and
| | - Hui Cai
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and Section of Nephrology, Atlanta Veterans Administration Medical Center, Decatur, Georgia
| | - Jeff M Sands
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and
| | - Guangping Chen
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and
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10
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Kim M, Tan YS, Cheng WC, Kingsbury TJ, Heimfeld S, Civin CI. MIR144 and MIR451 regulate human erythropoiesis via RAB14. Br J Haematol 2014; 168:583-97. [PMID: 25312678 DOI: 10.1111/bjh.13164] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 08/15/2014] [Indexed: 12/11/2022]
Abstract
Expression levels of MIR144 and MIR451 increase during erythropoiesis, a pattern that is conserved from zebrafish to humans. As these two miRs are expressed from the same polycistronic transcript, we manipulated MIR144 and MIR451 in human erythroid cells individually and together to investigate their effects on human erythropoiesis. Inhibition of endogenous human MIR451 resulted in decreased numbers of erythroid (CD71(hi) CD235a(hi) CD34(-) ) cells, consistent with prior studies in zebrafish and mice. In addition, inhibition of MIR144 impaired human erythroid differentiation, unlike in zebrafish and mouse studies where the functional effect of MIR144 on erythropoiesis was minimal. In this study, we found RAB14 is a direct target of both MIR144 and MIR451. As MIR144 and MIR451 expression increased during human erythropoiesis, RAB14 protein expression decreased. Enforced RAB14 expression phenocopied the effect of MIR144 and/or MIR451 depletion, whereas shRNA-mediated RAB14 knockdown protected cells from MIR144 and/or MIR451 depletion-mediated erythropoietic inhibition. RAB14 knockdown increased the frequency and number of erythroid cells, increased β-haemoglobin expression, and decreased CBFA2T3 expression during human erythropoiesis. In summary, we utilized MIR144 and MIR451 to identify RAB14 as a novel physiological inhibitor of human erythropoiesis.
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Affiliation(s)
- MinJung Kim
- Departments of Physiology and Pediatrics, Center for Stem Cell Biology & Regenerative Medicine, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
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11
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Abstract
UT-A and UT-B families of urea transporters consist of multiple isoforms that are subject to regulation of both acutely and by long-term measures. This chapter provides a brief overview of the expression of the urea transporter forms and their locations in the kidney. Rapid regulation of UT-A1 results from the combination of phosphorylation and membrane accumulation. Phosphorylation of UT-A1 has been linked to vasopressin and hyperosmolality, although through different kinases. Other acute influences on urea transporter activity are ubiquitination and glycosylation, both of which influence the membrane association of the urea transporter, again through different mechanisms. Long-term regulation of urea transport is most closely associated with the environment that the kidney experiences. Low-protein diets may influence the amount of urea transporter available. Conditions of osmotic diuresis, where urea concentrations are low, will prompt an increase in urea transporter abundance. Although adrenal steroids affect urea transporter abundance, conflicting reports make conclusions tenuous. Urea transporters are upregulated when P2Y2 purinergic receptors are decreased, suggesting a role for these receptors in UT regulation. Hypercalcemia and hypokalemia both cause urine concentration deficiencies. Urea transporter abundances are reduced in aging animals and animals with angiotensin-converting enzyme deficiencies. This chapter will provide information about both rapid and long-term regulation of urea transporters and provide an introduction into the literature.
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Affiliation(s)
- Janet D Klein
- Renal Division, Department of Medicine and Department of Physiology, Emory University School of Medicine, WMB Room 3319B, 1639 Pierce Drive, NE, Atlanta, GA, 30322, USA,
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