DOCSLIB.ORG

Investigating the Role of Chloride in Endocytic Organelle Acidification

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Investigating the Role of Chloride in Endocytic Organelle Acidification Investigating the role of chloride in endocytic organelle acidification By Mary R. Weston A dissertation submitted to Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy Baltimore, Maryland December 2017 © Mary R. Weston All rights reserved ABSTRACT Endocytic organelles maintain their characteristic, essential internal pH using the V-type ATPase H+-pump. Accumulation of H+ generates a voltage across the membrane; an additional ion, known as a counterion, must move to dissipate charge buildup. Chloride (Cl-) has been hypothesized to be an important counterion in the endosomal pathway, but its role is still debated. This thesis seeks to explore the role of counterions and the proteins that facilitate their movements in the acidification of clathrin-coated vesicles (CCVs), a subset of early endosomes, and lysosomes. We confirmed previous work showing that isolated bovine brain CCVs acidify in the presence of external Cl-, independent of the monovalent cations present. While unsuccessful at identifying the protein responsible for the observed anion transport, we used a new approach to confirm that most brain CCVs are synaptic vesicles. Secondly, because acidification in isolated lysosomes is Cl--dependent and the lysosomal protein ClC-7, a Cl-/H+ antiporter, moves Cl- into the organelles, this protein has been suggested to mediate such counterion movement. However, live cell ClC-7 knockout (KO) mouse lysosomes have the same pH as WT. We generated mice with a liver-specific deletion of ClC-7 to test these results in isolated lysosomes and live cells in parallel. While isolated ClC-7 KO lysosomes showed a drastic decrease in Cl--facilitated acidification, lysosomal pH was similar in WT and KO hepatocytes, even during metabolic and base challenges. Lastly, we present two patients with an identical pathogenic de novo variant in CLCN7, who display hypopigmentation, a delay in motor skills, abnormal liver/spleen/kidneys, and failure to thrive, but no osteopetrosis. Patient fibroblasts contain large vacuoles scattered throughout the cytoplasm that do not consistently stain for lysosomal markers, and ii possess a vast increase in the lysosomal-like compartments that stain for Lamp1, a lysosomal protein. Lysosomal pH in cultured patient fibroblasts are more acidic than the neonatal controls and heterologous expression of the mutant ClC-7 in Xenopus oocytes revealed substantial increases in transport activity. These results suggest a novel gain-of- function for this Cl-/H+ antiporter, one of the first reported instances of lysosomal hyperacidification, and shows that ClC-7 plays a role in lysosomal pH. Overall, this work contributes to the field of organelle acidification and brings us closer to understanding how organelles use counterions to assist in and regulate pH. Advisor/primary thesis reader: Joseph Mindell, M.D., Ph.D. Secondary thesis readers: Kenton Swartz, Ph.D. Beverly Wendland, Ph.D. iii Acknowledgements Graduate school has been a great challenge and an adventure. I have learned so much and am grateful to all those who helped and supported me over the years. First and foremost, I would like to thank my mentor, Dr. Joseph Mindell, for providing me with support and guidance throughout my graduate work. I am so thankful that I had the opportunity to work with someone who constantly challenged me to develop a thoughtful and rigorous approach to science. Thank you for your patience, encouragement, and for knowing that I would come out on the other side. The Mindell lab has been a fun place to scientifically “grow up”. Thank you to the current and past members for the atmosphere, the advice, and the food (specifically, birthday cakes, bagels, and babkas). I am especially grateful to Dr. Sara Lioi for teaching me about cells and to Dr. Christopher Mulligan for acting as my surrogate "older graduate student" when I first started. Additional thanks go to the members of the 3B and 3D pods. It has been amazing to be surrounded by so many kind people who foster a creative and collaborative scientific environment. Thank you to all my collaborators. It has been lovely working with and learning from you all, especially Dr. Anowarul Amin and Dr. Ralu Nicoli. Thank you to my wonderful thesis committee. Dr. Kenton Swartz and Dr. Beverly Wendland have provided constant support and guidance throughout my graduate work and I am grateful for their helpful scientific discussions and mentorship. Additionally, I received a lot of support from the kind people in the GPP, the professors and administrators at the JHU program, and OITE. I would specifically like to thank Dr. Orna Cohen-Fix and Julia Jarvis for listening to my science woes and encouraging me to carry on. iv I had some lovely and encouraging teachers during my high school and undergrad years who encouraged me on my path. Of those, I would like to specifically thank Mr. Kennedy for sparking my interest in science and Dr. Frank Roberto for keeping that spark alive. I have been fortunate to have had so many amazing friends over the years and many of you have made a lasting impact. Throughout graduate school, I am so happy that Senta, Kristie, Annie, Angel, and Sara shared in this adventure. Thank you to Gobi Thillai for being my person. I am eternally grateful for your advice, support, and patience through this graduate process. Thank you for making me laugh, for your healthy dose of reality through this process, and the constant reminder to enjoy life and not take things too seriously. I am so blessed to have my family. Thank you to my parents, Jeff and Karen. Thank you for providing me a solid foundation in both learning and in life. You always provided unwavering support and taught me to approach the world with kindness. I am grateful for my grandparents who are so encouraging and are some of my life role models. I strive to be as wise and humble as you. Then there are my crazy/fun/weird siblings, Rachel, David, and Eve. Thank you for being my biggest, most consistent cheerleaders, especially during those late-night phone calls. They say you can't choose your family but, given the option, I could not have done better. v TABLE OF CONTENTS ABSTRACT……………………………………………………………………..…..…ii ACKNOWLEDGEMENTS………………………………………………………..…iv TABLE OF CONTENTS…………………………………………………………..…vi LISTS OF FIGURES AND TABLES……………………..……..……………….….viii Chapter 1: Introduction pH in the endocytic pathway.………………………………………...…………...……...1 The V-ATPase generates a pH gradient in endocytic organelles…………………..…….3 The electrogenic V-ATPase requires counterions to allow organelle acidification….…..6 Endosomal acidification……………………….…………………………………..……..8 Early study of endosomal acidification……………………………………….….9 The diverse family of ClC transporters and channels………..…………..……....11 ClC-5 facilitates Cl--dependent acidification in early endosomes……………….14 Additional proteins with known and suggested roles in endosomal acidification…..……………………………………………………………..…...16 CCVs display Cl--dependent acidification via an unidentified protein….….…...20 Lysosomal acidification Lysosomes are dynamic signaling centers that rely on pH for function…….......22 Acidification and counterion study in isolated lysosomes.……………………...25 Candidate proteins that facilitate lysosomal counterion flux…………………....28 CFTR…………………………………………………………………………….28 ClC-7 ClC-7 facilitates acidification in isolated lysosomes……………………29 Loss of ClC-7 causes osteopetrosis and neurodegeneration…………….30 ClC-7 is not required for lysosomal acidification in live lysosomes? .....31 The importance of ClC-7 as a transporter vs. channel…………………..31 Cation channels that may assist in lysosomal acidification……………………. 34 Other roles for ClC-7: tissue/condition specific? ……………………………….37 Other roles for ClC-7: protein/protein interactions……………………………...38 What is the role of ClC-7? ……………………………………………………... 40 Is ClC-7 important for lysosomal pH maintenance? ……………………………41 Characterizing a de novo ClC-7 mutation in patients…………………………....43 Thesis aims………………………………………………….…………………………...44 vi Chapter 2: Characterizing chloride-dependent acidification in brain clathrin-coated vesicles Abstract…………………………………………………………………………………..46 Introduction………………………………………………………………….……..….....48 Materials and methods………………………………………………………….………..52 Results……………………………………………………………………….….………..60 Discussion……………………………………………………………………...………...78 Chapter 3: Probing the role of ClC-7 in hepatocyte lysosomal pH maintenance Abstract………………………………………………………………………..…………85 Introduction……………………………………………………………………………....87 Materials and methods…………………………………………………………….……..90 Results…………………………………………………………………………………...96 Discussion………………………………………………………………………………112 Chapter 4: A de novo CLCN7 mutation decreases intralysosomal pH and leads to a novel disorder of cutaneous albinism, lysosomal storage and neurodegeneration Abstract………………….……………………………………………………………...119 Introduction……………………………………………………………………………..120 Materials and methods………………………………………..……………………….. 122 Results…………………………………………………………………………………. 128 Discussion………………………………………………………………………………143 Chapter 5: Concluding remarks ……………………………….……………………149 LITERATURE CITED…………………………………………………………….....156 CURRICULUM VITAE………………..…………………………………………….168 vii LIST OF FIGURES Chapter 1 Figure 1-1: The endosome/lysosome system……………………………………………..2 Figure 1-2: Crystal structure of a eukaryotic ClC transporter…………………………...12 Figure 1-3: The ClC family of channels and transporters……………………………….13 Chapter 2 Figure 2-1: The isolated CCV sample is highly enriched
Load more

Recommended publications
  • Cystine–Glutamate Antiporter Xct Deficiency Suppresses Tumor Growth While Preserving Antitumor Immunity
    Cystine–glutamate antiporter xCT deficiency suppresses tumor growth while preserving antitumor immunity Michael D. Arensmana, Xiaoran S. Yanga, Danielle M. Leahya, Lourdes Toral-Barzaa, Mary Mileskia, Edward C. Rosfjorda, Fang Wanga, Shibing Dengb, Jeremy S. Myersa, Robert T. Abrahamb, and Christina H. Enga,1 aOncology Research & Development, Pfizer, Pearl River, NY 10965; and bOncology Research & Development, Pfizer, San Diego, CA 92121 Edited by William G. Kaelin Jr., Dana-Farber Cancer Institute and Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, and approved April 2, 2019 (received for review September 1, 2018) T cell-invigorating cancer immunotherapies have near-curative Thus, tumor cells may rely on xCT to fulfill the majority of their potential. However, their clinical benefit is currently limited, as cysteine and GSH needs by importing cystine. only a fraction of patients respond, suggesting that these regimens Inhibition of xCT has been investigated as a therapeutic may benefit from combination with tumor-targeting treatments. As strategy for cancer based on observations that elevated xCT ex- oncogenic progression is accompanied by alterations in metabolic pression on tumor cells correlates with poor prognosis (10–12) pathways, tumors often become heavily reliant on antioxidant and that inhibition of xCT in preclinical studies suppresses tumor machinery and may be susceptible to increases in oxidative stress. growth (10, 12–14). However, these studies relied heavily on the The cystine–glutamate antiporter xCT is frequently overexpressed in use of sulfasalazine, a clinical compound used for the treatment cancer and fuels the production of the antioxidant glutathione; thus, of rheumatoid arthritis, ulcerative colitis, and Crohn’s disease.
    [Show full text]
  • Biological Membranes and Transport Membranes Define the External
    Biological Membranes and Transport Membranes define the external boundaries of cells and regulate the molecular traffic across that boundary; in eukaryotic cells, they divide the internal space into discrete compartments to segregate processes and components. Membranes are flexible, self-sealing, and selectively permeable to polar solutes. Their flexibility permits the shape changes that accompany cell growth and movement (such as amoeboid movement). With their ability to break and reseal, two membranes can fuse, as in exocytosis, or a single membrane-enclosed compartment can undergo fission to yield two sealed compartments, as in endocytosis or cell division, without creating gross leaks through cellular surfaces. Because membranes are selectively permeable, they retain certain compounds and ions within cells and within specific cellular compartments, while excluding others. Membranes are not merely passive barriers. Membranes consist of just two layers of molecules and are therefore very thin; they are essentially two-dimensional. Because intermolecular collisions are far more probable in this two-dimensional space than in three-dimensional space, the efficiency of enzyme-catalyzed processes organized within membranes is vastly increased. The Molecular Constituents of Membranes Molecular components of membranes include proteins and polar lipids, which account for almost all the mass of biological membranes, and carbohydrate present as part of glycoproteins and glycolipids. Each type of membrane has characteristic lipids and proteins. The relative proportions of protein and lipid vary with the type of membrane, reflecting the diversity of biological roles (as shown in table 12-1, see below). For example, plasma membranes of bacteria and the membranes of mitochondria and chloroplasts, in which many enzyme-catalyzed processes take place, contain more protein than lipid.
    [Show full text]
  • The Role of Cell Membrane Information Reception, Processing, and Communication in the Structure and Function of Multicellular Tissue
    International Journal of Molecular Sciences Review The Role of Cell Membrane Information Reception, Processing, and Communication in the Structure and Function of Multicellular Tissue Robert A. Gatenby Departments of Radiology and Integrated Mathematical Oncology, Moffitt Cancer Center, Tampa, FL 33612, USA; robert.gatenby@moffitt.org Received: 9 July 2019; Accepted: 18 July 2019; Published: 24 July 2019 Abstract: Investigations of information dynamics in eukaryotic cells focus almost exclusively on heritable information in the genome. Gene networks are modeled as “central processors” that receive, analyze, and respond to intracellular and extracellular signals with the nucleus described as a cell’s control center. Here, we present a model in which cellular information is a distributed system that includes non-genomic information processing in the cell membrane that may quantitatively exceed that of the genome. Within this model, the nucleus largely acts a source of macromolecules and processes information needed to synchronize their production with temporal variations in demand. However, the nucleus cannot produce microsecond responses to acute, life-threatening perturbations and cannot spatially resolve incoming signals or direct macromolecules to the cellular regions where they are needed. In contrast, the cell membrane, as the interface with its environment, can rapidly detect, process, and respond to external threats and opportunities through the large amounts of potential information encoded within the transmembrane ion gradient. Our model proposes environmental information is detected by specialized protein gates within ion-specific transmembrane channels. When the gate receives a specific environmental signal, the ion channel opens and the received information is communicated into the cell via flow of a specific ion species (i.e., K+, Na+, 2+ 2+ Cl−, Ca , Mg ) along electrochemical gradients.
    [Show full text]
  • Transport of Sugars
    BI84CH32-Frommer ARI 29 April 2015 12:34 Transport of Sugars Li-Qing Chen,1,∗ Lily S. Cheung,1,∗ Liang Feng,3 Widmar Tanner,2 and Wolf B. Frommer1 1Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305; email: [email protected] 2Zellbiologie und Pflanzenbiochemie, Universitat¨ Regensburg, 93040 Regensburg, Germany 3Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305 Annu. Rev. Biochem. 2015. 84:865–94 Keywords First published online as a Review in Advance on glucose, sucrose, carrier, GLUT, SGLT, SWEET March 5, 2015 The Annual Review of Biochemistry is online at Abstract biochem.annualreviews.org Soluble sugars serve five main purposes in multicellular organisms: as sources This article’s doi: of carbon skeletons, osmolytes, signals, and transient energy storage and as 10.1146/annurev-biochem-060614-033904 transport molecules. Most sugars are derived from photosynthetic organ- Copyright c 2015 by Annual Reviews. isms, particularly plants. In multicellular organisms, some cells specialize All rights reserved in providing sugars to other cells (e.g., intestinal and liver cells in animals, ∗ These authors contributed equally to this review. photosynthetic cells in plants), whereas others depend completely on an ex- Annu. Rev. Biochem. 2015.84:865-894. Downloaded from www.annualreviews.org ternal supply (e.g., brain cells, roots and seeds). This cellular exchange of Access provided by b-on: Universidade de Lisboa (UL) on 09/05/16. For personal use only. sugars requires transport proteins to mediate uptake or release from cells or subcellular compartments. Thus, not surprisingly, sugar transport is criti- cal for plants, animals, and humans.
    [Show full text]
  • Renal Membrane Transport Proteins and the Transporter Genes
    Techno e lo n g Gowder, Gene Technology 2014, 3:1 e y G Gene Technology DOI; 10.4172/2329-6682.1000e109 ISSN: 2329-6682 Editorial Open Access Renal Membrane Transport Proteins and the Transporter Genes Sivakumar J T Gowder* Qassim University, College of Applied Medical Sciences, Buraidah, Kingdom of Saudi Arabia Kidney this way, high sodium diet favors urinary sodium concentration [9]. AQP2 has a role in hereditary and acquired diseases affecting urine- In humans, the kidneys are a pair of bean-shaped organs about concentrating mechanisms [10]. AQP2 regulates antidiuretic action 10 cm long and located on either side of the vertebral column. The of arginine vasopressin (AVP). The urinary excretion of this protein is kidneys constitute for less than 1% of the weight of the human body, considered to be an index of AVP signaling activity in the renal system. but they receive about 20% of blood pumped with each heartbeat. The Aquaporins are also considered as markers for chronic renal allograft renal artery transports blood to be filtered to the kidneys, and the renal dysfunction [11]. vein carries filtered blood away from the kidneys. Urine, the waste fluid formed within the kidney, exits the organ through a duct called the AQP4 ureter. The kidney is an organ of excretion, transport and metabolism. This gene encodes a member of the aquaporin family of intrinsic It is a complicated organ, comprising various cell types and having a membrane proteins. These proteins function as water-selective channels neatly designed three dimensional organization [1]. Due to structural in the plasma membrane.
    [Show full text]
  • Passive and Active Transport
    Passive and Active Transport 1. Thermodynamics of transport 2. Passive-mediated transport 3. Active transport neuron, membrane potential, ion transport Membranes • Provide barrier function – Extracellular – Organelles • Barrier can be overcome by „transport proteins“ – To mediate transmembrane movements of ions, Na+, K+ – Nutrients, glucose, amino acids etc. – Water (aquaporins) 1) Thermodynamics of Transport • Aout <-> Ain (ressembles a chemical equilibration) o‘ • GA - G A = RT ln [A] • ∆GA = GA(in) - GA(out) = RT ln ([A]in/[A]out) • GA: chemical potential of A o‘ • G A: chemical potential of standard state of A • If membrane has a potential, i.e., plasma membrane: -100mV (inside negative) then GA is termed the electrochemical potential of A Two types of transport across a membrane: o Nonmediated transport occurs by passive diffusion, i.e., O2, CO2 driven by chemical potential gradient, i.e. cannot occur against a concentration gradient o Mediated transport occurs by dedicated transport proteins 1. Passive-mediated transport/facilitated diffusion: [high] -> [low] 2. Active transport: [low] -> [high] May require energy in form of ATP or in form of a membrane potential 2) Passive-mediated transport Substances that are too large or too polar to diffuse across the bilayer must be transported by proteins: carriers, permeases, channels and transporters A) Ionophores B) Porins C) Ion Channels D) Aquaporins E) Transport Proteins A) Ionophores Organic molecules of divers types, often of bacterial origin => Increase the permeability of a target membrane for ions, frequently antibiotic, result in collapse of target membrane potential by ion equilibration 1. Carrier Ionophore, make ion soluble in membrane, i.e. valinomycin, 104 K+/sec 2.
    [Show full text]
  • AQP3 and AQP5—Potential Regulators of Redox Status in Breast Cancer
    molecules Review AQP3 and AQP5—Potential Regulators of Redox Status in Breast Cancer Lidija Milkovi´c and Ana Cipakˇ Gašparovi´c* Division of Molecular Medicine, Ruder¯ Boškovi´cInstitute, HR-10000 Zagreb, Croatia; [email protected] * Correspondence: [email protected]; Tel.: +385-1-457-1212 Abstract: Breast cancer is still one of the leading causes of mortality in the female population. Despite the campaigns for early detection, the improvement in procedures and treatment, drastic improvement in survival rate is omitted. Discovery of aquaporins, at first described as cellular plumbing system, opened new insights in processes which contribute to cancer cell motility and proliferation. As we discover new pathways activated by aquaporins, the more we realize the complexity of biological processes and the necessity to fully understand the pathways affected by specific aquaporin in order to gain the desired outcome–remission of the disease. Among the 13 human aquaporins, AQP3 and AQP5 were shown to be significantly upregulated in breast cancer indicating their role in the development of this malignancy. Therefore, these two aquaporins will be discussed for their involvement in breast cancer development, regulation of oxidative stress and redox signalling pathways leading to possibly targeting them for new therapies. Keywords: AQP3; AQP5; oxidative stress Citation: Milkovi´c,L.; Cipakˇ 1. Introduction Gašparovi´c,A. AQP3 and Despite the progress in research and treatment procedures, cancer still remains the AQP5—Potential Regulators of Redox leading cause of death. Today, cancer is targeted via different approaches which is deter- Status in Breast Cancer. Molecules mined by diagnosis, tumour marker expression, and specific mutations.
    [Show full text]
  • Evidence Supporting an Antimicrobial Origin of Targeting Peptides to Endosymbiotic Organelles
    cells Article Evidence Supporting an Antimicrobial Origin of Targeting Peptides to Endosymbiotic Organelles Clotilde Garrido y, Oliver D. Caspari y , Yves Choquet , Francis-André Wollman and Ingrid Lafontaine * UMR7141, Institut de Biologie Physico-Chimique (CNRS/Sorbonne Université), 13 Rue Pierre et Marie Curie, 75005 Paris, France; [email protected] (C.G.); [email protected] (O.D.C.); [email protected] (Y.C.); [email protected] (F.-A.W.) * Correspondence: [email protected] These authors contributed equally to this work. y Received: 19 June 2020; Accepted: 24 July 2020; Published: 28 July 2020 Abstract: Mitochondria and chloroplasts emerged from primary endosymbiosis. Most proteins of the endosymbiont were subsequently expressed in the nucleo-cytosol of the host and organelle-targeted via the acquisition of N-terminal presequences, whose evolutionary origin remains enigmatic. Using a quantitative assessment of their physico-chemical properties, we show that organelle targeting peptides, which are distinct from signal peptides targeting other subcellular compartments, group with a subset of antimicrobial peptides. We demonstrate that extant antimicrobial peptides target a fluorescent reporter to either the mitochondria or the chloroplast in the green alga Chlamydomonas reinhardtii and, conversely, that extant targeting peptides still display antimicrobial activity. Thus, we provide strong computational and functional evidence for an evolutionary link between organelle-targeting and antimicrobial peptides. Our results support the view that resistance of bacterial progenitors of organelles to the attack of host antimicrobial peptides has been instrumental in eukaryogenesis and in the emergence of photosynthetic eukaryotes. Keywords: Chlamydomonas; targeting peptides; antimicrobial peptides; primary endosymbiosis; import into organelles; chloroplast; mitochondrion 1.
    [Show full text]
  • Regulation of Apoptosis-Associated Lysosomal Membrane Permeabilization
    Linköping University Post Print Regulation of apoptosis-associated lysosomal membrane permeabilization Ann-Charlotte Johansson, Hanna Appelqvist, Cathrine Nilsson, Katarina Kågedal, Karin Roberg and Karin Öllinger N.B.: When citing this work, cite the original article. The original publication is available at www.springerlink.com: Ann-Charlotte Johansson, Hanna Appelqvist, Cathrine Nilsson, Katarina Kågedal, Karin Roberg and Karin Öllinger, Regulation of apoptosis-associated lysosomal membrane permeabilization, 2010, APOPTOSIS, (15), 5, 527-540. http://dx.doi.org/10.1007/s10495-009-0452-5 Copyright: Springer Science Business Media http://www.springerlink.com/ Postprint available at: Linköping University Electronic Press http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-55061 REGULATION OF APOPTOSIS-ASSOCIATED LYSOSOMAL MEMBRANE PERMEABILIZATION Ann-CharlotteJohansson1, Hanna Appelqvist2, Cathrine Nilsson1,2, Katarina Kågedal2, Karin Roberg1,3, Karin Öllinger2 1 Division of Otorhinolaryngology, Linköping University Hospital, Linköping, Sweden 2 Division of Experimental Pathology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden 3 Division of Otorhinolaryngology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden Correspondence: Ann-Charlotte Johansson, Division of Otorhinolaryngology, Linköping University Hospital, SE-581 85 Linköping, Sweden Phone: +46-13-221525, Fax: +46-13-221529, E-mail: [email protected] ABSTRACT Lysosomal membrane permeabilization (LMP) occurs in response to a large variety of cell death stimuli causing release of cathepsins from the lysosomal lumen into the cytosol where they participate in apoptosis signaling. In some settings, apoptosis induction is dependent on an early release of cathepsins, while under other circumstances LMP occurs late in the cell death process and contributes to amplification of the death signal.
    [Show full text]
  • Structure, Function, and Localization of Aquaporins: Their Possible Implications on Gamete Cryopreservation
    Review Structure, function, and localization of aquaporins: their possible implications on gamete cryopreservation A.D. Sales1, C.H. Lobo2, A.A. Carvalho1, A.A. Moura2 and A.P.R. Rodrigues1 1Laboratório de Manipulação de Oócitos e Folículos Ovarianos Pré-Antrais, Rede Nordeste de Biotecnologia, Universidade Estadual do Ceará, Fortaleza, CE, Brasil 2Grupo de Pesquisa em Biologia da Reprodução, Departamento de Zootecnia, Universidade Federal do Ceará, Fortaleza, CE, Brasil Corresponding author: A.P.R. Rodrigues E-mail: [email protected] Genet. Mol. Res. 12 (4): 6718-6732 (2013) Received April 10, 2013 Accepted October 15, 2013 Published December 13, 2013 DOI http://dx.doi.org/10.4238/2013.December.13.5 ABSTRACT. The discovery of water channels (aquaporins, AQPs) was a landmark event for the clarification of water transport through the plasma membrane. AQPs belong to a family of intrinsic membrane proteins that act as selective channels for water and for solutes such as glycerol and urea. AQPs were found in different tissues and organs, including male and female reproductive systems. In the swine female reproductive system, the AQPs were localized in the uterus, oviduct, and ovary, as well as in the granulosa cells from primordial follicles. Knowing the involvement of AQPs with the male and female germ cells, as well as their acknowledged role in transporting water through the plasma membrane, the research of these proteins in cryopreservation processes becomes essential. Thus, this review aims to describe the structure and function of AQPs in membranes, highlighting their role Genetics and Molecular Research 12 (4): 6718-6732 (2013) ©FUNPEC-RP www.funpecrp.com.br Overview and role of aquaporins on gamete cryopreservation 6719 in the reproductive system (male and female).
    [Show full text]
  • Amino Acid Transporters As Tetraspanin TM4SF5 Binding Partners Jae Woo Jung1,Jieonkim2,Eunmikim2 and Jung Weon Lee 1,2
    Jung et al. Experimental & Molecular Medicine (2020) 52:7–14 https://doi.org/10.1038/s12276-019-0363-7 Experimental & Molecular Medicine REVIEW ARTICLE Open Access Amino acid transporters as tetraspanin TM4SF5 binding partners Jae Woo Jung1,JiEonKim2,EunmiKim2 and Jung Weon Lee 1,2 Abstract Transmembrane 4 L6 family member 5 (TM4SF5) is a tetraspanin that has four transmembrane domains and can be N- glycosylated and palmitoylated. These posttranslational modifications of TM4SF5 enable homophilic or heterophilic binding to diverse membrane proteins and receptors, including growth factor receptors, integrins, and tetraspanins. As a member of the tetraspanin family, TM4SF5 promotes protein-protein complexes for the spatiotemporal regulation of the expression, stability, binding, and signaling activity of its binding partners. Chronic diseases such as liver diseases involve bidirectional communication between extracellular and intracellular spaces, resulting in immune-related metabolic effects during the development of pathological phenotypes. It has recently been shown that, during the development of fibrosis and cancer, TM4SF5 forms protein-protein complexes with amino acid transporters, which can lead to the regulation of cystine uptake from the extracellular space to the cytosol and arginine export from the lysosomal lumen to the cytosol. Furthermore, using proteomic analyses, we found that diverse amino acid transporters were precipitated with TM4SF5, although these binding partners need to be confirmed by other approaches and in functionally relevant studies. This review discusses the scope of the pathological relevance of TM4SF5 and its binding to certain amino acid transporters. 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; Introduction on the plasma membrane and the mitochondria, lyso- Importing and exporting biological matter in and out of some, and other intracellular organelles.
    [Show full text]
  • Membrane Transport Quiz
    Membrane Transport Quiz 1. Which of the following is an example of extracellular fluid? a. Cytosol b. Plasma c. Interstitial Fluid d. Both b and c 2. Which of the following correctly describes passive transport? a. the cell uses ATP in passive transport b. most pumps are examples of passive transport c. diffusion is an example of passive transport d. exocytosis is an example of passive transport 3. Simple diffusion occurs ______________. a. with transporters in the cell membrane b. directly across the cell membrane c. through exocytosis d. through endocytosis 4. Which of the following is an example of active transport? a. Filtration b. Osmosis c. Endocytosis d. Exocytosis e. Both c and d 5. Which type of active transport uses ATP directly? a. Primary Active Transport b. Secondary Active Transport c. Both a and b 6. Which of the following is an example of receptor mediated endocytosis? a. Phagocytosis b. Primary Active Transport c. Exocytosis d. ALL are For use with TCC iTunes University Membrane Transport Lecture. 1 Developed by: Martha Kutter 2009 for the Learning Commons at Tallahassee Community College. 7. A transporter that moves one type of particle in one direction is _______________. a. Uniporter b. Symporter c. Antiporter 8. A transporter the moves two different particles in two different directions is ________. a. Endocytosis b. Exocytosis c. Uniporter d. Symporter e. Antiporter 9. Which of the following is an example of a primary active transporter? a. Na+/Ca2+ transporter on cardiac contractile cells b. Na+ channels on neurons c. Na+/K+ ATPase on all cells d.
    [Show full text]