1
|
More KJ, Kaur H, Simpson AGB, Spiegel FW, Dacks JB. Contractile vacuoles: a rapidly expanding (and occasionally diminishing?) understanding. Eur J Protistol 2024; 94:126078. [PMID: 38688044 DOI: 10.1016/j.ejop.2024.126078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 05/02/2024]
Abstract
Osmoregulation is the homeostatic mechanism essential for the survival of organisms in hypoosmotic and hyperosmotic conditions. In freshwater or soil dwelling protists this is frequently achieved through the action of an osmoregulatory organelle, the contractile vacuole. This endomembrane organelle responds to the osmotic challenges and compensates by collecting and expelling the excess water to maintain the cellular osmolarity. As compared with other endomembrane organelles, this organelle is underappreciated and under-studied. Here we review the reported presence or absence of contractile vacuoles across eukaryotic diversity, as well as the observed variability in the structure, function, and molecular machinery of this organelle. Our findings highlight the challenges and opportunities for constructing cellular and evolutionary models for this intriguing organelle.
Collapse
Affiliation(s)
- Kiran J More
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Harpreet Kaur
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Alastair G B Simpson
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada; Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Frederick W Spiegel
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic; Centre for Life's Origins and Evolution, Department of Genetics, Evolution, & Environment, University College, London, United Kingdom.
| |
Collapse
|
2
|
Docampo R. Advances in the cellular biology, biochemistry, and molecular biology of acidocalcisomes. Microbiol Mol Biol Rev 2024; 88:e0004223. [PMID: 38099688 PMCID: PMC10966946 DOI: 10.1128/mmbr.00042-23] [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] [Indexed: 02/04/2024] Open
Abstract
SUMMARYAcidocalcisomes are organelles conserved during evolution and closely related to the so-called volutin granules of bacteria and archaea, to the acidocalcisome-like vacuoles of yeasts, and to the lysosome-related organelles of animal species. All these organelles have in common their acidity and high content of polyphosphate and calcium. They are characterized by a variety of functions from storage of phosphorus and calcium to roles in Ca2+ signaling, osmoregulation, blood coagulation, and inflammation. They interact with other organelles through membrane contact sites or by fusion, and have several enzymes, pumps, transporters, and channels.
Collapse
Affiliation(s)
- Roberto Docampo
- Department of Cellular Biology, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| |
Collapse
|
3
|
Ren D, Liu R, Yan X, Zhang Q, Zeng X, Yuan X. Intensive stretch-activated CRT-PMCA1 feedback loop promoted apoptosis of myoblasts through Ca 2+ overloading. Apoptosis 2022; 27:929-945. [PMID: 35976579 DOI: 10.1007/s10495-022-01759-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2022] [Indexed: 11/29/2022]
Abstract
Mechanical stretch exerted pro-apoptotic effect on myoblasts, the mechanism of which is currently unknown. Intracellular Ca2+ accumulation has been implicated in stretch-induced apoptosis. calreticulin (CRT) and plasma membrane Ca2+ transporting ATPase 1 (PMCA1) are two critical components of Ca2+ signaling system participating in intracellular Ca2+ homeostasis. In this study, we explored the contribution of CRT and PMCA1 in mediating stretch-induced Ca2+ accumulation and apoptosis of myoblasts. Stretching stimuli elevated level of CRT while inhibited activity of PMCA1. Moreover, there were bidirectional regulations between CRT and PMCA1, which formed the positive feedback loop leading to continuous increment of CRT level and repression of PMCA1 activity, in stretched myoblasts. Specifically, increased CRT level inhibited PMCA1 activity via suppressing Calmodulin (CaM), while reduced PMCA1 activity promoted CRT expression through activating p38MAPK pathway. Thus, the CRT-CaM-PMCA1 and PMCA1-p38MAPK-CRT pathways constituted a close cycle comprising CRT, PMCA1, CaM and p38MAPK. Inhibition of both CaM and p38MAPK affected the other three factors in stretched myoblasts. Circulation of the vicious cycle resulted in escalated Ca2+ overloading in myoblasts under continuous stretching stimuli. CRT knock-down, PMCA1 overexpression, and p38MAPK inhibition all attenuated the raised intracellular Ca2+ level and ameliorated myoblast apoptosis in the stretching environment. Conversely, CRT overexpression, PMCA1 knock-down, and CaM inhibition all aggravated stretch-induced Ca2+ overloading and myoblast apoptosis. A positive feedback loop between CRT and PMCA1 was activated in stretched myoblasts, which contributed to intracellular Ca2+ accumulation and resultant myoblast apoptosis.
Collapse
Affiliation(s)
- Dapeng Ren
- Department of Stomatology Medical Center, Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Central Laboratory of Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Department of Orthodontics, School of Stomatology, Qingdao University, Qingdao, China
| | - Ran Liu
- Department of Stomatology Medical Center, Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Central Laboratory of Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Xiao Yan
- Department of Stomatology Medical Center, Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Central Laboratory of Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Department of Orthodontics, School of Stomatology, Qingdao University, Qingdao, China
| | - Qiang Zhang
- Department of Stomatology Medical Center, Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Central Laboratory of Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Department of Orthodontics, School of Stomatology, Qingdao University, Qingdao, China
| | - Xuemin Zeng
- Department of Stomatology Medical Center, Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Central Laboratory of Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.,Department of Orthodontics, School of Stomatology, Qingdao University, Qingdao, China
| | - Xiao Yuan
- Department of Stomatology Medical Center, Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China. .,Central Laboratory of Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China. .,Department of Orthodontics, School of Stomatology, Qingdao University, Qingdao, China.
| |
Collapse
|
4
|
Rodríguez-Durán J, Gallardo JP, Alba Soto CD, Gómez KA, Potenza M. The Kinetoplastid-Specific Protein TcCAL1 Plays Different Roles During In Vitro Differentiation and Host-Cell Invasion in Trypanosoma cruzi. Front Cell Infect Microbiol 2022; 12:901880. [PMID: 35846750 PMCID: PMC9280158 DOI: 10.3389/fcimb.2022.901880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
In the pathogen Typanosoma cruzi, the calcium ion (Ca2+) regulates key processes for parasite survival. However, the mechanisms decoding Ca2+ signals are not fully identified or understood. Here, we investigate the role of a hypothetical Ca2+-binding protein named TcCAL1 in the in vitro life cycle of T. cruzi. Results showed that the overexpression of TcCAL1 fused to a 6X histidine tag (TcCAL1-6xHis) impaired the differentiation of epimastigotes into metacyclic trypomastigotes, significantly decreasing metacyclogenesis rates. When the virulence of transgenic metacyclic trypomastigotes was explored in mammalian cell invasion assays, we found that the percentage of infection was significantly higher in Vero cells incubated with TcCAL1-6xHis-overexpressing parasites than in controls, as well as the number of intracellular amastigotes. Additionally, the percentage of Vero cells with adhered metacyclic trypomastigotes significantly increased in samples incubated with TcCAL1-6xHis-overexpressing parasites compared with controls. In contrast, the differentiation rates from metacyclic trypomastigotes to axenic amastigotes or the epimastigote proliferation in the exponential phase of growth have not been affected by TcCAL1-6xHis overexpression. Based on our findings, we speculate that TcCAL1 exerts its function by sequestering intracellular Ca2+ by its EF-hand motifs (impairing metacyclogenesis) and/or due to an unknown activity which could be amplified by the ion binding (promoting cell invasion). This work underpins the importance of studying the kinetoplastid-specific proteins with unknown functions in pathogen parasites.
Collapse
Affiliation(s)
- Jessica Rodríguez-Durán
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
| | - Juan Pablo Gallardo
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
| | - Catalina Dirney Alba Soto
- Instituto de Microbiología y Parasitología Médica, Departamento de Microbiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Karina Andrea Gómez
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
| | - Mariana Potenza
- Laboratorio de Biología e Inmunología de las Infecciones por Tripanosomátidos, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor Torres”—CONICET, Buenos Aires, Argentina
- *Correspondence: Mariana Potenza, ;
| |
Collapse
|
5
|
Manchola Varón NC, Dos Santos GRRM, Colli W, Alves MJM. Interaction With the Extracellular Matrix Triggers Calcium Signaling in Trypanosoma cruzi Prior to Cell Invasion. Front Cell Infect Microbiol 2021; 11:731372. [PMID: 34671568 PMCID: PMC8521164 DOI: 10.3389/fcimb.2021.731372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 08/23/2021] [Indexed: 11/26/2022] Open
Abstract
Trypanosoma cruzi, the etiological agent of Chagas disease in humans, infects a wide variety of vertebrates. Trypomastigotes, the parasite infective forms, invade mammalian cells by a still poorly understood mechanism. Adhesion of tissue culture- derived trypomastigotes to the extracellular matrix (ECM) prior to cell invasion has been shown to be a relevant part of the process. Changes in phosphorylation, S-nitrosylation, and nitration levels of proteins, in the late phase of the interaction (2 h), leading to the reprogramming of both trypomastigotes metabolism and the DNA binding profile of modified histones, were described by our group. Here, the involvement of calcium signaling at a very early phase of parasite interaction with ECM is described. Increments in the intracellular calcium concentrations during trypomastigotes-ECM interaction depends on the Ca2+ uptake from the extracellular medium, since it is inhibited by EGTA or Nifedipine, an inhibitor of the L-type voltage gated Ca2+ channels and sphingosine-dependent plasma membrane Ca2+ channel, but not by Vanadate, an inhibitor of the plasma membrane Ca2+-ATPase. Furthermore, Nifedipine inhibits the invasion of host cells by tissue culture- derived trypomastigotes in a dose-dependent manner, reaching 95% inhibition at 100 µM Nifedipine. These data indicate the importance of both Ca2+ uptake from the medium and parasite-ECM interaction for host-cell invasion. Previous treatment of ECM with protease abolishes the Ca2+ uptake, further reinforcing the possibility that these events may be connected. The mitochondrion plays a relevant role in Ca2+ homeostasis in trypomastigotes during their interaction with ECM, as shown by the increment of the intracellular Ca2+ concentration in the presence of Antimycin A, in contrast to other calcium homeostasis disruptors, such as Cyclopiazonic acid for endoplasmic reticulum and Bafilomycin A for acidocalcisome. Total phosphatase activity in the parasite decreases in the presence of Nifedipine, EGTA, and Okadaic acid, implying a role of calcium in the phosphorylation level of proteins that are interacting with the ECM in tissue culture- derived trypomastigotes. In summary, we describe here the increment of Ca2+ at an early phase of the trypomastigotes interaction with ECM, implicating both nifedipine-sensitive Ca2+ channels in the influx of Ca2+ and the mitochondrion as the relevant organelle in Ca2+ homeostasis. The data unravel a complex sequence of events prior to host cell invasion itself.
Collapse
Affiliation(s)
- Nubia Carolina Manchola Varón
- Laboratory of Biochemistry of Parasites, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | | | - Walter Colli
- Laboratory of Biochemistry of Parasites, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Maria Julia M Alves
- Laboratory of Biochemistry of Parasites, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| |
Collapse
|
6
|
Pérez-Gordones MC, Ramírez-Iglesias JR, Benaim G, Mendoza M. A store-operated Ca 2+-entry in Trypanosoma equiperdum: Physiological evidences of its presence. Mol Biochem Parasitol 2021; 244:111394. [PMID: 34216677 DOI: 10.1016/j.molbiopara.2021.111394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 02/06/2023]
Abstract
The Trypanosomatidae family encompasses many unicellular organisms responsible of several tropical diseases that affect humans and animals. Livestock tripanosomosis caused by Trypanosoma brucei brucei (T. brucei), Trypanosoma equiperdum (T. equiperdum) and Trypanosoma evansi (T. evansi), have a significant socio-economic impact and limit animal protein productivity throughout the intertropical zones of the world. Similarly, to all organisms, the maintenance of Ca2+ homeostasis is vital for these parasites, and the mechanism involved in the intracellular Ca2+ regulation have been widely described. However, the evidences related to the mechanisms responsible for the Ca2+ entry are scarce. Even more, to date the presence of a store-operated Ca2+ channel (SOC) has not been reported. Despite the apparent absence of Orai and STIM-like proteins in these parasites, in the present work we demonstrate the presence of a store-operated Ca2+-entry (SOCE) in T. equiperdum, using physiological techniques. This Ca2+-entry is induced by thapsigargin (TG) and 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ), and inhibited by 2-aminoethoxydiphenyl borate (2APB). Additionally, the use of bioinformatics techniques allowed us to identify putative transient receptor potential (TRP) channels, present in members of the Trypanozoon family, which would be possible candidates responsible for the SOCE described in the present work in T. equiperdum.
Collapse
Affiliation(s)
- María C Pérez-Gordones
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela
| | - José R Ramírez-Iglesias
- Group of Neglected and Emerging Diseases, Epidemiology and Biodiversity, Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador
| | - Gustavo Benaim
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela; Instituto de Estudios Avanzados (IDEA), Caracas, Venezuela
| | - Marta Mendoza
- Centro de Estudios Biomédicos y Veterinarios, Instituto de Estudios Científicos y Tecnológicos (IDECYT), Universidad Nacional Experimental Simón Rodríguez, Caracas, Venezuela.
| |
Collapse
|
7
|
Benaim G, Paniz-Mondolfi AE, Sordillo EM, Martinez-Sotillo N. Disruption of Intracellular Calcium Homeostasis as a Therapeutic Target Against Trypanosoma cruzi. Front Cell Infect Microbiol 2020; 10:46. [PMID: 32133302 PMCID: PMC7040492 DOI: 10.3389/fcimb.2020.00046] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/24/2020] [Indexed: 12/15/2022] Open
Abstract
There is no effective cure for Chagas disease, which is caused by infection with the arthropod-borne parasite, Trypanosoma cruzi. In the search for new drugs to treat Chagas disease, potential therapeutic targets have been identified by exploiting the differences between the mechanisms involved in intracellular Ca2+ homeostasis, both in humans and in trypanosomatids. In the trypanosomatid, intracellular Ca2+ regulation requires the concerted action of three intracellular organelles, the endoplasmic reticulum, the single unique mitochondrion, and the acidocalcisomes. The single unique mitochondrion and the acidocalcisomes also play central roles in parasite bioenergetics. At the parasite plasma membrane, a Ca2+-−ATPase (PMCA) with significant differences from its human counterpart is responsible for Ca2+ extrusion; a distinctive sphingosine-activated Ca2+ channel controls Ca2+ entrance to the parasite interior. Several potential anti-trypansosomatid drugs have been demonstrated to modulate one or more of these mechanisms for Ca2+ regulation. The antiarrhythmic agent amiodarone and its derivatives have been shown to exert trypanocidal effects through the disruption of parasite Ca2+ homeostasis. Similarly, the amiodarone-derivative dronedarone disrupts Ca2+ homeostasis in T. cruzi epimastigotes, collapsing the mitochondrial membrane potential (ΔΨm), and inducing a large increase in the intracellular Ca2+ concentration ([Ca2+]i) from this organelle and from the acidocalcisomes in the parasite cytoplasm. The same general mechanism has been demonstrated for SQ109, a new anti-tuberculosis drug with potent trypanocidal effect. Miltefosine similarly induces a large increase in the [Ca2+]i acting on the sphingosine-activated Ca2+ channel, the mitochondrion and acidocalcisomes. These examples, in conjunction with other evidence we review herein, strongly support targeting Ca2+ homeostasis as a strategy against Chagas disease.
Collapse
Affiliation(s)
- Gustavo Benaim
- Instituto de Estudios Avanzados, Caracas, Venezuela.,Facultad de Ciencias, Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, Venezuela
| | - Alberto E Paniz-Mondolfi
- Instituto de Estudios Avanzados, Caracas, Venezuela.,Department of Pathology, Molecular, and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Emilia Mia Sordillo
- Department of Pathology, Molecular, and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Institute for Health Sciences, Mount Sinai St. Luke's & Mount Sinai West, New York, NY, United States
| | | |
Collapse
|
8
|
Schoijet AC, Sternlieb T, Alonso GD. Signal Transduction Pathways as Therapeutic Target for Chagas Disease. Curr Med Chem 2019; 26:6572-6589. [PMID: 31218950 DOI: 10.2174/0929867326666190620093029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 12/26/2018] [Accepted: 02/20/2019] [Indexed: 01/23/2023]
Abstract
Trypanosomatids are a group of flagellated unicellular eukaryotes, causing serious human diseases including Chagas disease (Trypanosoma cruzi), sleeping sickness (Trypanosoma brucei spp.) and Leishmaniasis (Leishmania spp.). The second messenger cAMP is involved in numerous and fundamental processes in these parasites including differentiation between stages, proliferation, osmoregulation, oxidative stress and quorum sensing. Interestingly, its signaling pathway is quite different from that of mammals, including structurally different adenylyl cyclases, the shortage of orthologous effector proteins and the absence of G-protein-coupled-receptors, among others. These characteristics make the proteins involved in these transduction pathways good candidates for therapeutic targets. However, the identification of new unknown druggable targets involves extensive research time and is economically very expensive, making difficult the transition from basic research to the clinical phase. Trypanosomatid PDEs have characteristic binding pockets that allow for a differential inhibition from their human orthologs. Modification in the approved drugs for human to convert them into trypanocidal treatments could lead to more effective therapies, shorter lab time and lower costs. In view of the fact that kinetoplastid PDEs are highly conserved with their mammalian counterparts, and since there are already numerous drugs on the market against human PDEs, the drug repositioning approach is highly promising. The development of new technologies, higher government and industrial involvement and more scientists committed to basic investigation, are the key to ultimately find an effective treatment and cure for the neglected tropical diseases.
Collapse
Affiliation(s)
- Alejandra Cecilia Schoijet
- Laboratorio de Senalizacion y Mecanismos Adaptativos en Tripanosomatidos, Instituto de Investigaciones en Ingenieria Genetica y Biologia Molecular "Dr. Hector N. Torres"; Vuelta de Obligado 2490 (C1428ADN), Buenos Aires, Argentina
| | - Tamara Sternlieb
- Laboratorio de Senalizacion y Mecanismos Adaptativos en Tripanosomatidos, Instituto de Investigaciones en Ingenieria Genetica y Biologia Molecular "Dr. Hector N. Torres"; Vuelta de Obligado 2490 (C1428ADN), Buenos Aires, Argentina
| | - Guillermo Daniel Alonso
- Laboratorio de Senalizacion y Mecanismos Adaptativos en Tripanosomatidos, Instituto de Investigaciones en Ingenieria Genetica y Biologia Molecular "Dr. Hector N. Torres"; Vuelta de Obligado 2490 (C1428ADN), Buenos Aires, Argentina.,Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| |
Collapse
|
9
|
Meade JC. P-type transport ATPases in Leishmania and Trypanosoma. ACTA ACUST UNITED AC 2019; 26:69. [PMID: 31782726 PMCID: PMC6884021 DOI: 10.1051/parasite/2019069] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 11/12/2019] [Indexed: 01/12/2023]
Abstract
P-type ATPases are critical to the maintenance and regulation of cellular ion homeostasis and membrane lipid asymmetry due to their ability to move ions and phospholipids against a concentration gradient by utilizing the energy of ATP hydrolysis. P-type ATPases are particularly relevant in human pathogenic trypanosomatids which are exposed to abrupt and dramatic changes in their external environment during their life cycles. This review describes the complete inventory of ion-motive, P-type ATPase genes in the human pathogenic Trypanosomatidae; eight Leishmania species (L. aethiopica, L. braziliensis, L. donovani, L. infantum, L. major, L. mexicana, L. panamensis, L. tropica), Trypanosoma cruzi and three Trypanosoma brucei subspecies (Trypanosoma brucei brucei TREU927, Trypanosoma brucei Lister strain 427, Trypanosoma brucei gambiense DAL972). The P-type ATPase complement in these trypanosomatids includes the P1B (metal pumps), P2A (SERCA, sarcoplasmic-endoplasmic reticulum calcium ATPases), P2B (PMCA, plasma membrane calcium ATPases), P2D (Na+ pumps), P3A (H+ pumps), P4 (aminophospholipid translocators), and P5B (no assigned specificity) subfamilies. These subfamilies represent the P-type ATPase transport functions necessary for survival in the Trypanosomatidae as P-type ATPases for each of these seven subfamilies are found in all Leishmania and Trypanosoma species included in this analysis. These P-type ATPase subfamilies are correlated with current molecular and biochemical knowledge of their function in trypanosomatid growth, adaptation, infectivity, and survival.
Collapse
Affiliation(s)
- John C Meade
- Department of Microbiology and Immunology, School of Medicine, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA
| |
Collapse
|
10
|
Rodriguez‐Duran J, Pinto‐Martinez A, Castillo C, Benaim G. Identification and electrophysiological properties of a sphingosine‐dependent plasma membrane Ca
2+
channel in
Trypanosoma cruzi. FEBS J 2019; 286:3909-3925. [DOI: 10.1111/febs.14947] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 10/31/2018] [Accepted: 06/01/2019] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Gustavo Benaim
- Instituto de Estudios Avanzados (IDEA) Caracas Venezuela
- Instituto de Biología Experimental Facultad de Ciencias Universidad Central de Venezuela Caracas Venezuela
| |
Collapse
|
11
|
Ramakrishnan S, Docampo R. Membrane Proteins in Trypanosomatids Involved in Ca 2+ Homeostasis and Signaling. Genes (Basel) 2018; 9:E304. [PMID: 29921754 PMCID: PMC6027440 DOI: 10.3390/genes9060304] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/11/2018] [Accepted: 06/14/2018] [Indexed: 01/10/2023] Open
Abstract
Calcium ion (Ca2+) serves as a second messenger for a variety of cell functions in trypanosomes. Several proteins in the plasma membrane, acidocalcisomes, endoplasmic reticulum, and mitochondria are involved in its homeostasis and in cell signaling roles. The plasma membrane has a Ca2+ channel for its uptake and a plasma membrane-type Ca2+-ATPase (PMCA) for its efflux. A similar PMCA is also located in acidocalcisomes, acidic organelles that are the primary Ca2+ store and that possess an inositol 1,4,5-trisphosphate receptor (IP₃R) for Ca2+ efflux. Their mitochondria possess a mitochondrial calcium uniporter complex (MCUC) for Ca2+ uptake and a Ca2+/H⁺ exchanger for Ca2+ release. The endoplasmic reticulum has a sarcoplasmic-endoplasmic reticulum-type Ca2+-ATPase (SERCA) for Ca2+ uptake but no Ca2+ release mechanism has been identified. Additionally, the trypanosomatid genomes contain other membrane proteins that could potentially bind calcium and await further characterization.
Collapse
Affiliation(s)
- Srinivasan Ramakrishnan
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
| | - Roberto Docampo
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
| |
Collapse
|
12
|
Identification and characterization of a calmodulin binding domain in the plasma membrane Ca 2+-ATPase from Trypanosoma equiperdum. Mol Biochem Parasitol 2018; 222:51-60. [PMID: 29752964 DOI: 10.1016/j.molbiopara.2018.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 04/19/2018] [Accepted: 04/23/2018] [Indexed: 02/01/2023]
Abstract
The plasma membrane Ca2+-ATPase (PMCA) from trypanosomatids lacks a classical calmodulin (CaM) binding domain, although CaM stimulated activities have been detected by biochemical assays. Recently we proposed that the Trypanosoma equiperdum CaM-sensitive PMCA (TePMCA) contains a potential 1-18 CaM-binding motif at the C-terminal region of the pump. In the present study, we evaluated the potential CaM-binding motifs using CaM from Trypanosoma cruzi and either the recombinant full length TePMCA C-terminal sequence (P14) or synthetic peptides comprising different regions of the C-terminal domain. We demonstrated that P14 and a synthetic peptide corresponding to residues 1037-1062 (which contains the predicted 1-18 binding motif) competed efficiently for binding to TcCaM, exhibiting similar IC50s of 200 nM. A stable complex of this peptide and TcCaM was formed in the presence of Ca2+, as determined by native-polyacrylamide gel electrophoresis. A predicted structure obtained by molecular docking showed an interaction of the 1-18 binding motif with the Ca2+/CaM complex. Moreover, when the peptide was incubated with CaM and Ca2+, a blue shift in the tryptophan fluorescence spectrum (from 350 to 329 nm) was observed. Substitutions at W1039 and F1056, strongly decreased both CaM-peptide interaction and the complex assembly. Our results demonstrated the presence of a functional 1-18 motif at the TePMCA C-terminal domain. Furthermore, on the basis of spectrofluorometric assays and the resulting structure modeled by docking we propose that the L1042 and W1060 residues might also participate as anchors to form a 1-4-18-22 motif.
Collapse
|
13
|
Evidence of the presence of a calmodulin-sensitive plasma membrane Ca 2+-ATPase in Trypanosoma equiperdum. Mol Biochem Parasitol 2017; 213:1-11. [PMID: 28213174 DOI: 10.1016/j.molbiopara.2017.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 02/09/2017] [Accepted: 02/10/2017] [Indexed: 01/01/2023]
Abstract
Trypanosoma equiperdum belongs to the subgenus Trypanozoon, which has a significant socio-economic impact by limiting animal protein productivity worldwide. Proteins involved in the intracellular Ca2+ regulation are prospective chemotherapeutic targets since several drugs used in experimental treatment against trypanosomatids exert their action through the disruption of the parasite intracellular Ca2+ homeostasis. Therefore, the plasma membrane Ca2+-ATPase (PMCA) is considered as a potential drug target. This is the first study revealing the presence of a PMCA in T. equiperdum (TePMCA) showing that it is calmodulin (CaM) sensitive, revealed by ATPase activity, western-blot analysis and immuno-absorption assays. The cloning sequence for TePMCA encodes a 1080 amino acid protein which contains domains conserved in all PMCAs so far studied. Molecular modeling predicted that the protein has 10 transmembrane and three cytoplasmic loops which include the ATP-binding site, the phosphorylation domain and Ca2+ translocation site. Like all PMCAs reported in other trypanosomatids, TePMCA lacks a classic CaM binding domain. Nevertheless, this enzyme presents in the C-terminal tail a region of 28 amino acids (TeC28), which most likely adopts a helical conformation within a 1-18 CaM binding motif. Molecular docking between Trypanosoma cruzi CaM (TcCaM) and TeC28 shows a significant similarity with the CaM-C28PMCA4b reference structure (2kne). TcCaM-TeC28 shows an anti-parallel interaction, the peptide wrapped by CaM and the anchor buried in the hydrophobic pocket, structural characteristic described for similar complexes. Our results allows to conclude that T. equiperdum possess a CaM-sensitive PMCA, which presents a non-canonical CaM binding domain that host a 1-18 motif.
Collapse
|
14
|
Lipophorin Drives Lipid Incorporation and Metabolism in Insect Trypanosomatids. Protist 2015; 166:297-309. [DOI: 10.1016/j.protis.2015.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 03/24/2015] [Accepted: 04/08/2015] [Indexed: 01/04/2023]
|
15
|
Docampo R, Huang G. Calcium signaling in trypanosomatid parasites. Cell Calcium 2014; 57:194-202. [PMID: 25468729 DOI: 10.1016/j.ceca.2014.10.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 11/29/2022]
Abstract
Calcium ion (Ca(2+)) is an important second messenger in trypanosomatids and essential for their survival although prolonged high intracellular Ca(2+) levels lead to cell death. As other eukaryotic cells, trypanosomes use two sources of Ca(2+) for generating signals: Ca(2+) release from intracellular stores and Ca(2+) entry across the plasma membrane. Ca(2+) release from intracellular stores is controlled by the inositol 1,4,5-trisphosphate receptor (IP3R) that is located in acidocalcisomes, acidic organelles that are the primary Ca(2+) reservoir in these cells. A plasma membrane Ca(2+)-ATPase controls the cytosolic Ca(2+) levels and a number of pumps and exchangers are responsible for Ca(2+) uptake and release from intracellular compartments. The trypanosomatid genomes contain a wide variety of signaling and regulatory proteins that bind Ca(2+) as well as many Ca(2+)-binding proteins that await further characterization. The mitochondrial Ca(2+) transporters of trypanosomatids have an important role in the regulation of cell bioenergetics and flagellar Ca(2+) appears to have roles in sensing the environment. In trypanosomatids in which an intracellular life cycle is present, Ca(2+) signaling is important for host cell invasion.
Collapse
Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA 30620, USA; Departamento de Patologia Clínica, State University of Campinas, Campinas, SP 13083, Brazil.
| | - Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA 30620, USA
| |
Collapse
|
16
|
De Cicco NNT, Pereira MG, Corrêa JR, Andrade-Neto VV, Saraiva FB, Chagas-Lima AC, Gondim KC, Torres-Santos EC, Folly E, Saraiva EM, Cunha-E-Silva NL, Soares MJ, Atella GC. LDL uptake by Leishmania amazonensis: involvement of membrane lipid microdomains. Exp Parasitol 2012; 130:330-40. [PMID: 22381219 DOI: 10.1016/j.exppara.2012.02.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 02/10/2012] [Accepted: 02/13/2012] [Indexed: 02/02/2023]
Abstract
Leishmania amazonensis lacks a de novo mechanism for cholesterol synthesis and therefore must scavenge this lipid from the host environment. In this study we show that the L. amazonensis takes up and metabolizes human LDL(1) particles in both a time and dose-dependent manner. This mechanism implies the presence of a true LDL receptor because the uptake is blocked by both low temperature and by the excess of non-labelled LDL. This receptor is probably associated with specific microdomains in the membrane of the parasite, such as rafts, because this process is blocked by methyl-β-cyclodextrin (MCBD). Cholesteryl ester fluorescently-labeled LDL (BODIPY-cholesteryl-LDL) was used to follow the intracellular distribution of this lipid. After uptake it was localized in large compartments along the parasite body. The accumulation of LDL was analyzed by flow cytometry using FITC-labeled LDL particles. Together these data show for the first time that L. amazonensis is able to compensate for its lack of lipid synthesis through the use of a lipid importing machinery largely based on the uptake of LDL particles from the host. Understanding the details of the molecular events involved in this mechanism may lead to the identification of novel targets to block Leishmania infection in human hosts.
Collapse
Affiliation(s)
- Nuccia N T De Cicco
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21.941-902, Brazil
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Ulrich PN, Jimenez V, Park M, Martins VP, Atwood J, Moles K, Collins D, Rohloff P, Tarleton R, Moreno SNJ, Orlando R, Docampo R. Identification of contractile vacuole proteins in Trypanosoma cruzi. PLoS One 2011; 6:e18013. [PMID: 21437209 PMCID: PMC3060929 DOI: 10.1371/journal.pone.0018013] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 02/22/2011] [Indexed: 11/19/2022] Open
Abstract
Contractile vacuole complexes are critical components of cell volume regulation
and have been shown to have other functional roles in several free-living
protists. However, very little is known about the functions of the contractile
vacuole complex of the parasite Trypanosoma cruzi, the
etiologic agent of Chagas disease, other than a role in osmoregulation.
Identification of the protein composition of these organelles is important for
understanding their physiological roles. We applied a combined proteomic and
bioinfomatic approach to identify proteins localized to the contractile vacuole.
Proteomic analysis of a T. cruzi fraction enriched for
contractile vacuoles and analyzed by one-dimensional gel electrophoresis and
LC-MS/MS resulted in the addition of 109 newly detected proteins to the group of
expressed proteins of epimastigotes. We also identified different peptides that
map to at least 39 members of the dispersed gene family 1 (DGF-1) providing
evidence that many members of this family are simultaneously expressed in
epimastigotes. Of the proteins present in the fraction we selected several
homologues with known localizations in contractile vacuoles of other organisms
and others that we expected to be present in these vacuoles on the basis of
their potential roles. We determined the localization of each by expression as
GFP-fusion proteins or with specific antibodies. Six of these putative proteins
(Rab11, Rab32, AP180, ATPase subunit B, VAMP1, and phosphate transporter)
predominantly localized to the vacuole bladder. TcSNARE2.1, TcSNARE2.2, and
calmodulin localized to the spongiome. Calmodulin was also cytosolic. Our
results demonstrate the utility of combining subcellular fractionation,
proteomic analysis, and bioinformatic approaches for localization of organellar
proteins that are difficult to detect with whole cell methodologies. The CV
localization of the proteins investigated revealed potential novel roles of
these organelles in phosphate metabolism and provided information on the
potential participation of adaptor protein complexes in their biogenesis.
Collapse
Affiliation(s)
- Paul N. Ulrich
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Veronica Jimenez
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Miyoung Park
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Vicente P. Martins
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - James Atwood
- Complex Carbohydrate Research Center,
University of Georgia, Athens, Georgia, United States of America
| | - Kristen Moles
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Dalis Collins
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Peter Rohloff
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Rick Tarleton
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Silvia N. J. Moreno
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
| | - Ron Orlando
- Complex Carbohydrate Research Center,
University of Georgia, Athens, Georgia, United States of America
| | - Roberto Docampo
- Center for Tropical and Emerging Global
Diseases and Department of Cellular Biology, University of Georgia, Athens,
Georgia, United States of America
- * E-mail:
| |
Collapse
|
18
|
Jimenez V, Henriquez M, Galanti N, Riquelme G. Electrophysiological characterization of potassium conductive pathways in Trypanosoma cruzi. J Cell Biochem 2011; 112:1093-102. [DOI: 10.1002/jcb.23023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
19
|
Garcia-Marchan Y, Sojo F, Rodriguez E, Zerpa N, Malave C, Galindo-Castro I, Salerno M, Benaim G. Trypanosoma cruzi calmodulin: cloning, expression and characterization. Exp Parasitol 2009; 123:326-33. [PMID: 19703447 DOI: 10.1016/j.exppara.2009.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 07/27/2009] [Accepted: 08/18/2009] [Indexed: 11/17/2022]
Abstract
We have cloned and expressed calmodulin (CaM) from Trypanosoma cruzi, for the first time, to obtain large amounts of protein. CaM is a very well conserved protein throughout evolution, sharing 100% amino acid sequence identity between different vertebrates and 99% between trypanosomatids. However, there is 89% amino acid sequence identity between T. cruzi and vertebrate CaMs. The results demonstrate significant differences between calmodulin from T. cruzi and mammals. First, a polyclonal antibody developed in an egg-yolk system to the T. cruzi CaM recognizes the autologous CaM but not the CaM from rat. Second, it undergoes a larger increase in the alpha-helix content upon binding with Ca(2+), when compared to CaM from vertebrates. Finally, two classic CaM antagonists, calmidazolium and trifluoperazine, capable of inhibiting the action of CaM in mammals when assayed on the plasma membrane Ca(2+) pump, showed a significant loss of activity when assayed upon stimulation with the T. cruzi CaM.
Collapse
Affiliation(s)
- Yael Garcia-Marchan
- Centro de Biociencias y Medicina Molecular, Instituto de Estudios Avanzados (IDEA), Universidad Central de Venezuela, Caracas 1080, Bolivarian Republic of Venezuela
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Pérez-Gordones MC, Lugo MR, Winkler M, Cervino V, Benaim G. Diacylglycerol regulates the plasma membrane calcium pump from human erythrocytes by direct interaction. Arch Biochem Biophys 2009; 489:55-61. [PMID: 19631607 DOI: 10.1016/j.abb.2009.07.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 07/14/2009] [Accepted: 07/17/2009] [Indexed: 11/25/2022]
Abstract
The plasma membrane Ca(2+)-ATPase (PMCA) plays a key role in the regulation of the intracellular Ca(2+) concentration. Ethanol stimulates this Ca(2+) pump in an isoform-specific manner. On search for a physiological molecule that could mimic the effect of ethanol, we have previously demonstrated that some sphingolipids containing free "hydroxyl" groups, like ceramide, are able to stimulate the PMCA. Since diacylglycerol (DAG) structurally shares some characteristics with ceramide, we evaluate its effect on the PMCA. We demonstrated that DAG is a potent stimulator of this enzyme. The activation induced is additive to that produced by calmodulin, protein-kinase C and ethanol, which implies that DAG interacts with the PMCA through a different mechanism. Additionally, by different fluorescent approaches, we demonstrated a direct binding between PMCA and DAG. The results obtained in this work strongly suggest that DAG is a novel effector of the PMCA, acting by a direct interaction.
Collapse
Affiliation(s)
- Maria C Pérez-Gordones
- Instituto de Biología Experimental (IBE), Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela
| | | | | | | | | |
Collapse
|
21
|
Amiodarone destabilizes intracellular Ca2+ homeostasis and biosynthesis of sterols in Leishmania mexicana. Antimicrob Agents Chemother 2009; 53:1403-10. [PMID: 19164149 DOI: 10.1128/aac.01215-08] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leishmaniasis represents a serious public health problem worldwide. The first line of treatment is based on glucantime and pentostan, which generate toxic effects in treated patients. We have recently shown that amiodarone, frequently used as an antiarrhythmic, possesses activity against Trypanosoma cruzi through the disruption of mitochondrial Ca(2+) homeostasis and the inhibition of parasite ergosterol biosynthesis, specifically at the level of oxidosqualene cyclase activity (G. Benaim, J. Sanders, Y. Garcia-Marchan, C. Colina, R. Lira, A. Caldera, G. Payares, C. Sanoja, J. Burgos, A. Leon-Rossell, J. Concepcion, A. Schijman, M. Levin, E. Oldfield, and J. Urbina, J. Med. Chem. 49:892-899, 2006). Here we show that at therapeutic concentrations, amiodarone has a profound effect on the viability of Leishmania mexicana promastigotes. Additionally, its effect on the viability of the parasite was greater against intracellular amastigotes than against promastigotes, and it did not affect the host cell. Using fluorimetric and confocal microscopy techniques, we also demonstrated that the mechanism of action of amiodarone was related to the disruption of intracellular Ca(2+) homeostasis through a direct action not only on the mitochondria but also on the acidocalcisomes. On the other hand, analysis of the free sterols in promastigotes incubated with amiodarone showed that this drug also affected the biosynthesis of 5-dehydroepisterol, which results in squalene accumulation, thus suggesting that amiodarone inhibits the squalene epoxidase activity of the parasite. Taken together, the results obtained in the present work point to a more general effect of amiodarone in trypanosomatids, opening potential therapeutic possibilities for this infectious disease.
Collapse
|
22
|
Romani A. Regulation of magnesium homeostasis and transport in mammalian cells. Arch Biochem Biophys 2006; 458:90-102. [PMID: 16949548 DOI: 10.1016/j.abb.2006.07.012] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Accepted: 07/21/2006] [Indexed: 02/06/2023]
Abstract
Magnesium is the second most abundant cation within the cell after potassium and plays an important role in numerous biological functions. Several pieces of experimental evidence indicate that mammalian cells tightly regulate Mg(2+) content by precise control mechanisms operating at the level of Mg(2+) entry and efflux across the cell membrane, as well as at the level of intracellular Mg(2+) buffering and organelle compartmentation under resting conditions and following hormonal stimuli. This review will attempt to elucidate the mechanisms involved in hormonal-mediated Mg(2+) extrusion and accumulation, as well as the physiological implications of changes in cellular Mg(2+) content following hormonal stimuli.
Collapse
Affiliation(s)
- Andrea Romani
- Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4970, USA.
| |
Collapse
|
23
|
Pinheiro CM, Martins-Duarte ES, Ferraro RB, Fonseca de Souza AL, Gomes MT, Lopes AHCS, Vannier-Santos MA, Santos ALS, Meyer-Fernandes JR. Leishmania amazonensis: Biological and biochemical characterization of ecto-nucleoside triphosphate diphosphohydrolase activities. Exp Parasitol 2006; 114:16-25. [PMID: 16603157 DOI: 10.1016/j.exppara.2006.02.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 02/02/2006] [Accepted: 02/06/2006] [Indexed: 10/24/2022]
Abstract
The presence of Leishmania amazonensis ecto-nucleoside triphosphate triphosphohydrolase activities was demonstrated using antibodies against different NTPDase members by Western blotting, flow cytometry, and immunoelectron microscopy analysis. Living promastigote cells sequentially hydrolyzed the ATP molecule generating ADP, AMP, and adenosine, indicating that this surface enzyme may play a role in the salvage of purines from the extracellular medium. The L. amazonensis ecto-NTPDase activities were insensitive to Triton X-100, but they were enhanced by divalent cations, such as Mg(2+). In addition, the ecto-NTPDase activities decreased with time for 96 h when promastigotes were grown in vitro. On the other hand, these activities increased considerably when measured in living amastigote forms. Furthermore, the treatment with adenosine, a mediator of several relevant biological phenomena, induced a decrease in the reactivity with anti-CD39 antibody, raised against mammalian E-NTPDase, probably because of down regulation in the L. amazonensis ecto-NTPDase expression. Also, adenosine and anti-NTPDase antibodies induced a significant diminishing in the interaction between promastigotes of L. amazonensis and mouse peritoneal macrophages.
Collapse
Affiliation(s)
- Carla M Pinheiro
- Instituto de Bioquímica Médica (IBqM), Universidade Federal do Rio de Janeiro (UFRJ), Centro de Ciências da Saúde (CCS), Bloco H, Cidade Universitária, Ilha do Fundão, 21541-590 Rio de Janeiro, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Panizzutti R, de Souza Leite M, Pinheiro CM, Meyer-Fernandes JR. The occurrence of free d-alanine and an alanine racemase activity inLeishmania amazonensis. FEMS Microbiol Lett 2006; 256:16-21. [PMID: 16487314 DOI: 10.1111/j.1574-6968.2006.00064.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Free D-amino acids are implicated in several biological functions. This study examined the presence of D-alanine in Leishmania amazonensis. Measuring chiral amino acid content by high-performance liquid chromatography we detected a significant amount of free D-alanine in promastigotes of these parasites. D-alanine accounts for 8.9% of total free alanine and is found primarily in the soluble fraction. Specific racemization of L-alanine to D-alanine was detected in cell lysates and this enzyme activity was inhibited by D-cycloserine, an alanine racemase inhibitor. Furthermore, we were able to decrease this pool of D-amino acid by treating our cultures with D-cycloserine. We demonstrate for the first time the existence of a significant amount of free D-alanine in L. amazonensis and an alanine racemase activity present in cell lysates. The restriction of D-alanine to bacteria, some fungi and now in L. amazonensis opens a new perspective on treatment of diseases caused by these microorganisms.
Collapse
Affiliation(s)
- Rogério Panizzutti
- Departamento de Anatomia, ICB, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | |
Collapse
|
25
|
De Lima AR, Medina R, Uzcanga GL, Noris Suárez K, Contreras VT, Navarro MC, Arteaga R, Bubis J. Tight binding between a pool of the heterodimeric α/β tubulin and a protein kinase CK2 inTrypanosoma cruziepimastigotes. Parasitology 2005; 132:511-23. [PMID: 16332290 DOI: 10.1017/s0031182005009352] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 09/28/2005] [Accepted: 09/28/2005] [Indexed: 01/23/2023]
Abstract
Tubulin is the predominant phosphoprotein inTrypanosoma cruziepimastigotes and is phosphorylated by a protein kinase CK2. Interestingly, the presence or absence of divalent cations affected the solubilization of a pool of the parasite tubulin and the CK2 responsible for its phosphorylation. This fraction of tubulin and its kinase co-eluted using phosphocellulose, DEAE-Sepharose and Sephacryl S-300 chromatographies. Anti-α tubulin antibodies co-immunoprecipitated both tubulin and the CK2 responsible for its phosphorylation, and anti-CK2 α-subunit antibodies immunoprecipitated radioactively labelled α and β tubulin from phosphorylated epimastigote homogenates. Additionally, native polyacrylamide gel electrophoresis of the purified and radioactively labelled fraction containing tubulin and its kinase demonstrated the phosphorylation of a unique band that reacted with both anti-CK2 α-subunit and anti-tubulin antibodies. Together, these results establish a strong interaction between a pool of the heterodimeric α/β tubulin and a CK2 in this parasite. Hydrodynamic measurements indicated that theT. cruzitubulin-CK2 complex is globular with an estimated size of 145·4–147·5 kDa.
Collapse
Affiliation(s)
- A R De Lima
- Departamento de Biología Celular, Universidad Simón Bolívar, Apartado 89.000, Valle de Sartenejas, Caracas 1081-A, Venezuela
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Marchesini N, Vieira M, Luo S, Moreno SNJ, Docampo R. A Malaria Parasite-encoded Vacuolar H+-ATPase Is Targeted to the Host Erythrocyte. J Biol Chem 2005; 280:36841-7. [PMID: 16135514 DOI: 10.1074/jbc.m507727200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The asexual development of malaria parasites inside the erythrocyte is accompanied by changes in the composition, structure, and function of the host cell membrane and cytoplasm. The parasite exports a membrane network into the host cytoplasm and several proteins that are inserted into the erythrocyte membrane, although none of these proteins has been shown to have enzymatic activity. We report here that a functional malaria parasite-encoded vacuolar (V)-H(+)-ATPase is exported to the erythrocyte and localized in membranous structures and in the plasma membrane of the infected erythrocyte. This localization was determined by separation of parasite and erythrocyte membranes and determination of enzyme marker activities and by immunofluorescence microscopy assays using antibodies against the B subunit of the malarial V-H(+)-ATPase and erythrocyte (spectrins) and parasite (merozoite surface protein 1) markers. Our results suggest that this pump has a role in the maintenance of the intracellular pH (pH(i)) of the infected erythrocyte. Our results also indicate that although the pH(i) maintained by the V-H(+)-ATPase is important for maximum uptake of small metabolites at equilibrium, it does not appear to affect transport across the erythrocyte membrane and is, therefore, not involved in the previously described phenomenon of increased permeability of infected erythrocytes that is sensitive to chloride channel inhibitors (new permeation pathway). This constitutes the first report of the presence of a functional enzyme of parasite origin in the plasma membrane of its host.
Collapse
Affiliation(s)
- Norma Marchesini
- Department of Pathobiology and Center for Zoonoses Research, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA
| | | | | | | | | |
Collapse
|
27
|
Miranda K, Vercesi AE, Catisti R, De Souza W, Rodrigues CO, Docampo R. P-type Proton ATPases are Involved in Intracellular Calcium and Proton Uptake in the Plant Parasite Phytomonas francai. J Eukaryot Microbiol 2005; 52:55-60. [PMID: 15702981 DOI: 10.1111/j.1550-7408.2005.3309rr.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The use of digitonin to permeabilize the plasma membrane of promastigotes of Phytomonas francai allowed the identification of two non-mitochondrial Ca(2+) compartments; one sensitive to ionomycin and vanadate (neutral or alkaline), possibly the endoplasmic reticulum, and another sensitive to the combination of nigericin plus ionomycin (acidic), possibly the acidocalcisomes. A P-type (phospho-intermediate form) Ca(2+)-ATPase activity was found to be responsible for intracellular Ca(2+) transport in these cells, with no evidence of a mitochondrial Ca(2+) transport activity. ATP-driven acidification of internal compartments in cell lysates and cells mechanically permeabilized was assayed spectrophotometrically with acridine orange. This activity was inhibited by low concentrations of vanadate and digitonin, was insensitive to bafilomycin A(1), and stimulated by Na(+) ions. Taken together, our results indicate that P-type ATPases are involved in intracellular Ca(2+) and H(+) transport in promastigotes of P. francai.
Collapse
Affiliation(s)
- Kildare Miranda
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | | | | | | | | | | |
Collapse
|
28
|
Martinez R, Wang Y, Benaim G, Benchimol M, de Souza W, Scott DA, Docampo R. A proton pumping pyrophosphatase in the Golgi apparatus and plasma membrane vesicles of Trypanosoma cruzi. Mol Biochem Parasitol 2002; 120:205-13. [PMID: 11897126 DOI: 10.1016/s0166-6851(01)00456-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The proton pumping pyrophosphatase (H(+)-PPase) is an enzyme that has been identified in membranes of plant vacuoles, in the Golgi complex of plants and Chlamydomonas reinhardtii, and more recently in acidocalcisomes of different trypanosomatids and apicomplexan parasites. Immunofluorescence and immunoelectron microscopy studies using antibodies against the plant enzyme also suggested a plasma membrane localization in different stages of Trypanosoma cruzi. In this report we provide immunogold electron microscopy evidence of the presence of the H(+)-PPase in the Golgi complex and plasma membrane of epimastigotes of T. cruzi. Pyrophosphate promoted acidification of plasma membrane vesicles as determined using acridine orange. This activity was stimulated by K(+) ions, inhibited by the pyrophosphate analogs imidodiphosphate (IDP) and aminomethylenediphosphonate (AMDP) by KF, NaF and DCCD, and it had different responses to ions and inhibitors as compared with the activity present in acidocalcisomes. Surface localization of the H(+)-PPase was confirmed by experiments using biotinylation of cell surface proteins and immunoprecipitation with antibodies against H(+)-PPase. Taken together, these results are consistent with the presence of a functional H(+)-PPase in the plasma membrane of these parasites.
Collapse
Affiliation(s)
- Rosa Martinez
- Laboratory of Molecular Parasitology, Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL 61802, USA
| | | | | | | | | | | | | |
Collapse
|
29
|
Marchesini N, Ruiz FA, Vieira M, Docampo R. Acidocalcisomes are functionally linked to the contractile vacuole of Dictyostelium discoideum. J Biol Chem 2002; 277:8146-53. [PMID: 11748243 DOI: 10.1074/jbc.m111130200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mass-dense granules of Dictyostelium discoideum were shown to contain large amounts of phosphorus, magnesium, and calcium, as determined by x-ray microanalysis, either in situ or when purified using iodixanol gradient centrifugation. The high phosphorus content was due to the presence of pyrophosphate and polyphosphate, which were also present in the contractile vacuoles. Both organelles also possessed a vacuolar H(+)-ATPase, an H(+)-pyrophosphatase, and a Ca(2+)-ATPase, as determined by biochemical methods or by immunofluorescence microscopy. The H(+)-pyrophosphatase activity of isolated mass-dense granules was stimulated by potassium ions and inhibited by the pyrophosphate analogs aminomethylenediphosphonate and imidodiphosphate and by KF and N-ethylmaleimide in a dose-dependent manner. The mass-dense granules and the contractile vacuole appeared to contact each other when the cells were submitted to hyposmotic stress. Acetazolamide inhibited the carbonic anhydrase activity of the contractile vacuoles and prolonged their contraction cycle in a dose-dependent manner. Similar effects were observed with the anion exchanger inhibitor 4,4' -diisothiocyanatodihydrostilbene-2, 2' -disulfonic acid and the vacuolar H(+)-ATPase inhibitor bafilomycin A(1). Together, these results suggest that the mass-dense granules of D. discoideum are homologous to the acidocalcisomes described in protozoan parasites and are linked to the function of the contractile vacuole.
Collapse
Affiliation(s)
- Norma Marchesini
- Laboratory of Molecular Parasitology, Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA
| | | | | | | |
Collapse
|
30
|
Colina C, Cervino V, Benaim G. Ceramide and sphingosine have an antagonistic effect on the plasma-membrane Ca2+-ATPase from human erythrocytes. Biochem J 2002; 362:247-51. [PMID: 11829762 PMCID: PMC1222382 DOI: 10.1042/0264-6021:3620247] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The plasma-membrane Ca(2+)-ATPase is a key enzyme in the regulation of the intracellular Ca(2+) concentration. On the other hand, sphingolipids have been recognized recently as important second messengers, acting in many systems in combination with Ca(2+). In view of the fact that the Ca(2+)-ATPase is stimulated by ethanol, and since sphingolipids possess free hydroxy groups, we decided to study the possible effect of ceramide and sphingosine on this calcium pump. Here we show that ceramide stimulates the Ca(2+)-ATPase in a dose-dependent manner and additively to the activation observed in the presence of calmodulin or ethanol, when compared with any of these effectors added alone. Ceramide affects both the affinity for Ca(2+) and the V(max) of the enzyme. Furthermore, this second messenger also stimulates Ca(2+) transport in inside-out plasma-membrane vesicles from erythro cytes. Conversely, sphingosine, which is reported to act in many systems antagonistically with ceramide, showed an inhibitory effect on Ca(2+)-ATPase activity. This inhibition was also observed on the calmodulin-stimulated enzyme. These results, taken together, suggest that ceramide and sphingosine act antagonistically on the plasma-membrane Ca(2+)-ATPase. This is in accordance with the frequently reported opposite effect of these sphingolipids on intracellular Ca(2+) concentration.
Collapse
Affiliation(s)
- Claudia Colina
- Instituto de Biología Experimental, Facultad de Ciencias, Universidad Central de Venezuela, Apartado 47114, Caracas, Venezuela
| | | | | |
Collapse
|
31
|
Thomson L, Gadelha FR, Peluffo G, Vercesi AE, Radi R. Peroxynitrite affects Ca2+ transport in Trypanosoma cruzi. Mol Biochem Parasitol 1999; 98:81-91. [PMID: 10029311 DOI: 10.1016/s0166-6851(98)00149-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Macrophages play an important role against Trypanosoma cruzi infection, via superoxide, nitric oxide, and peroxynitrite production. Peroxynitrite has been shown to be highly cytotoxic against Trypanosoma cruzi epimastigotes. Calcium is involved in many vital functions of the parasites, being its intracellular concentration governed by several transport systems, involving mitochondrial and non-mitochondrial compartments. In this paper, we report the effect of peroxynitrite on the calcium uptake systems, as studied by digitonin-permeabilized trypanosomes in the presence of arsenazo III. Peroxynitrite, at biologically relevant concentrations produced within phagosomes (250-750 microM), inhibited calcium uptake in a dose-dependent manner. Peroxynitrite decreased the mitochondrial membrane potential obtained in the presence of tetramethyl-p-phenylenediamine (TMPD)/ascorbate. In addition, a decrease of the non-mitochondrial Ca(2+)-uptake, concomitant with the inactivation of a Ca(2+)-dependent ATPase activity, was observed. HPLC analyses of the cellular adenine nucleotide pool showed a time-dependent decrease of ATP content and energy charge of the parasite; however this drop in ATP levels was significantly delayed with respect to decrease of the ATP-dependent Ca(2+)-transport. We conclude that the disruption of calcium homeostasis by peroxynitrite may contribute to the observed cytotoxic effects of macrophages against T. cruzi.
Collapse
Affiliation(s)
- L Thomson
- Departamento de Bioquimica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | | | | | | | | |
Collapse
|
32
|
Marchesini N, Santander V, Machado-Domenech E. Diacylglycerol pyrophosphate: a novel metabolite in the Trypanosoma cruzi phosphatidic acid metabolism. FEBS Lett 1998; 436:377-81. [PMID: 9801152 DOI: 10.1016/s0014-5793(98)01169-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This work provides evidence that phosphatidic acid (PA) is metabolized to diacylglycerol pyrophosphate (DGPP) in Trypanosoma cruzi. Also the presence of the enzymatic activities involved in its regulation, phosphatidate kinase (PA-k) and phosphatidate phosphatase, is demonstrated. The increase of DGPP levels in T. cruzi epimastigotes or in its membrane fraction after exogenous PA addition or phospholipase (PLD) pre-treatment suggests that PA-k may be involved in the regulation of PA levels after its stimulation.
Collapse
Affiliation(s)
- N Marchesini
- Química Biológica, Facultad de Ciencias Exactas, Fisico-Químicas y Naturales, Universidad Nacional de Rio Cuarto, Córdoba, Argentina
| | | | | |
Collapse
|
33
|
Benaim G, Cervino V, Villalobo A. Comparative phosphorylation of calmodulin from trypanosomatids and bovine brain by calmodulin-binding protein kinases. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART C, PHARMACOLOGY, TOXICOLOGY & ENDOCRINOLOGY 1998; 120:57-65. [PMID: 9827017 DOI: 10.1016/s0742-8413(98)00006-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Calmodulin (CaM), a major intracellular Ca2+ receptor protein, has been identified and partially characterized in several trypanosomatids. The amino acid sequences of CaM from Trypanosoma cruzi and Trypanosoma brucei are known, while that from Leishmania mexicana is not. CaM from T. cruzi contains 18 amino acid substitutions, as compared with CaM from bovine brain. In addition, CaM from bovine brain contains two tyrosine residues (Tyr-99 and Tyr-138), while CaM from T. cruzi only contains Tyr-138. In the present work we show that a monoclonal antibody developed against the carboxyl-terminal region of bovine brain CaM fails to recognize CaM from both T. cruzi and L. mexicana. CaM from both parasites and from bovine brain were phosphorylated in vitro by a preparation of CaM-binding protein kinases enriched in the epidermal growth factor (EGF) receptor. Phosphoamino acids analysis demonstrated EGF-dependent phosphorylation of tyrosine residues in bovine brain CaM, while only trace amounts of tyrosine phosphorylation were detected in CaM from both trypanosomatids. These results demonstrate that the EGF receptor tyrosine kinase targets Tyr-99, but not Tyr-138, as the single major phosphorylatable residue of CaM. On the other hand, and in contrast to bovine brain CaM, there is a significant phosphorylation of serine residues in CaM from trypanosomatids which is activated by the EGF receptor via a protein-serine/threonine kinase cascade.
Collapse
Affiliation(s)
- G Benaim
- Instituto de Biología Experimental, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela.
| | | | | |
Collapse
|
34
|
Ponte-Sucre A, Campos Y, Fernandez M, Moll H, Mendoza-León A. Leishmania sp.: growth and survival are impaired by ion channel blockers. Exp Parasitol 1998; 88:11-9. [PMID: 9501844 DOI: 10.1006/expr.1998.4200] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present work we examined the effect of ion transport blockers on the growth and viability of Leishmania sp. and on the infection of macrophages by the parasite. 4-aminopyridine and glibenclamide block voltage-dependent and K+ ATP channels, respectively; amiloride is used to detect Na+ channels and Na+/H+ antiporters; and anthracene-9-carboxylic acid affects chloride channels. The EC50 for promastigote cultures of three strains of the Leishmania subgenus, namely, Leishmania (Leishmania) NR, Leishmania (Leishmania) amazonensis LTB0016, and Leishmania (Leishmania) major, at their stationary phase of growth, were, respectively, 39, 46, and 464 microM for 4-aminopyridine; 7, 0.8, and 10 microM for glibenclamide and 66, 170, and 10 microM for anthracene-9-carboxylic acid. The amiloride EC50 for NR was 264 microM and 10 microM for L. (L.) major, but was never reached for LTB0016. Higher concentrations of the drugs impaired the exponential growth of Leishmania promastigotes. These results suggest the susceptibility of Leishmania sp. to blockers associated with K+ and Cl- and to Na+ or Na+/H+ transport systems. Blockade of such systems might have impaired the survival of the parasites as promastigotes. In addition, it affected the persistence of parasites in host cells. Although the infection of the macrophage cell line J774 and peritoneal-exudate macrophages was not significantly decreased by concentrations of the drugs around the promastigotes' EC50, the survival of intracellular parasites decreased significantly in the presence of these drugs without affecting the viability of the macrophages. Some blockers consistently gave small EC50 and significantly decreased the infection process as well as the survival of intracellular parasites. Thus, elucidation of their mechanism of action in Leishmania is relevant, since they could represent a potential subject for the development of leishmanicidal drugs.
Collapse
Affiliation(s)
- A Ponte-Sucre
- Laboratory of Molecular Physiology, I.M.E., Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela
| | | | | | | | | |
Collapse
|
35
|
Mandal D, Mukherjee T, Sarkar S, Majumdar S, Bhaduri A. The plasma-membrane Ca2+-ATPase of Leishmania donovani is an extrusion pump for Ca2+. Biochem J 1997; 322 ( Pt 1):251-7. [PMID: 9078270 PMCID: PMC1218185 DOI: 10.1042/bj3220251] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Controlled exposure of Leishmania donovani promastigotes to hypotonic shock results in the formation of deflagellated unsealed ghosts of original polarity that largely retain the pellicular microtubular structure associated with plasma membrane of the parasite. Gentle shearing followed by suspension of the purified membrane in appropriate isotonic buffer containing Mg2+ (4mM) results in the formation of sealed everted vesicles. The presence of Mg2+ (4 mM) appears to be essential for efficient sealing and also to prevent leakiness. ATP-dependent Ca2+ accumulation can be demonstrated in these vesicles Km values for Ca2+ and ATP were 125 nM and 0.8 mM respectively. The accumulated Ca2+ reaches a concentration of 1.1 mM. Ca2+ uptake is completely inhibited by vanadate (40 microM) and several thiol-modifying agents. Using 5,5'-dithiobis-(2-nitrobenzoic acid) as the modifying agent, an excellent correlation between loss of enzyme activity and transport capability and their parallel regeneration in the presence of 2 mM dithiothreitol was demonstrated. Using 2'.7-bis(carboxyethyl)-5(6)-carboxyfluorescein as the fluorescent pH probe, it was observed that Ca2+ entry into the vesicles is accompanied by an outward movement of H+ from the vesicles. Taken together, this paper establishes that the high-affinity transmembrane Ca2+-ATPase [Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Majumdar, Mukherjee, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] is an extrusion pump for Ca2+ in this human pathogen.
Collapse
Affiliation(s)
- D Mandal
- Leishmania Group, Enzyme Division, Indian Institute of Chemical Biology, Calcutta, India
| | | | | | | | | |
Collapse
|
36
|
Vanderheyden N, Benaim G, Docampo R. The role of a H(+)-ATPase in the regulation of cytoplasmic pH in Trypanosoma cruzi epimastigotes. Biochem J 1996; 318 ( Pt 1):103-9. [PMID: 8761458 PMCID: PMC1217594 DOI: 10.1042/bj3180103] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cytoplasmic pH (pHi) regulation was studied in Trypanosoma cruzi epimastigotes using fluorescent probes. Steady-state pHi was maintained even in the absence of extracellular Na+ or K+, but was significantly decreased in the absence of Cl-. Acid-loaded epimastigotes regained normal pHi by a process that was ATP-dependent and sensitive to N-ethylmaleimide, dicyclohexyl-carbodi-imide and diethylstiboestrol, suggesting involvement of a H(+)-pumping ATPase. Recovery from an acid load was independent of extracellular Na+ or K+ and insensitive to omeprazole, vanadate and low concentrations of bafilomycin A1. Using the fluorescent probe bisoxonol to measure the membrane potential of intact cells, acid loading of epimastigotes was shown to result in a dicyclohexylcarbodi-imide-sensitive hyperpolarization, which suggests electrogenic pumping of protons across the plasma membrane. Addition of glucose, but not of 6-deoxyglucose, produced a transient cellular acidification of possible metabolic origin, and increased the rate of recovery from an acid load. Taken together, these results are consistent with an important role of a H(+)-ATPase in the regulation of pHi homoeostasis in T. cruzi.
Collapse
Affiliation(s)
- N Vanderheyden
- Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, IL 61801, USA
| | | | | |
Collapse
|
37
|
Suju M, Davila M, Poleo G, Docampo R, Benaim G. Phosphatidylethanol stimulates the plasma-membrane calcium pump from human erythrocytes. Biochem J 1996; 317 ( Pt 3):933-8. [PMID: 8760385 PMCID: PMC1217575 DOI: 10.1042/bj3170933] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Phosphatidylethanol is formed by "transphosphatidylation' of phospholipids with ethanol catalysed by phospholipase D and can be accumulated in the plasma membrane of mammalian cells after treatment of animals with ethanol. In the present work we show that phosphatidylalcohols, such as phosphatidylethanol and phosphatidylbutanol, produced a twofold stimulation of the Ca(2+)-ATPase activity of human erythrocytes. This stimulation occurs with the purified, solubilized enzyme as well as with ghost preparations, where the enzyme is in its natural lipidic environment and is different to that obtained with other acidic phospholipids such as phosphatidylserine. Addition of either phosphatidylserine, phosphatidylethanol or phosphatidylbutanol to the purified Ca(2+)-ATPase, or to ghosts preparations, increased the affinity of the enzyme for Ca2+ and the maximal velocity of the reaction as compared with controls in the absence of acidic phospholipids. However, in contrast with what occurs with phosphatidylserine, simultaneous addition of phosphatidyl-alcohols and calmodulin increased the affinity of the enzyme for Ca2+ to a greater extent than each added separately. When ethanol was added to either the purified erythrocyte Ca(2+)-ATPase or to erythrocyte-ghost preparations in the presence of acidic phospholipids, an additive effect was observed. There was an increase in the affinity for Ca2+ and in the maximal velocity of the reaction, well above the values obtained with ethanol or with the acidic phospholipids tested separately. These findings could have pharmacological importance. It is conceivable that the decrease in the intracellular Ca(2+) concentration that has been reported in erythrocytes as a result of ethanol intoxication could be due to the stimulation of the Ca(2+)-ATPase by the accumulated phosphatidylethanol, to a direct effect of ethanol on the enzyme or to an additive combination of both.
Collapse
Affiliation(s)
- M Suju
- Instituto de Biologia Experimental, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela
| | | | | | | | | |
Collapse
|
38
|
Ogueta S, Intosh GM, Téllez-Iñon MT. Regulation of Ca2+/calmodulin-dependent protein kinase from Trypanosoma cruzi. Mol Biochem Parasitol 1996; 78:171-83. [PMID: 8813687 DOI: 10.1016/s0166-6851(96)02622-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A multifunctional Ca2+/calmodulin-dependent protein kinase (TcCaM K) was purified and characterized from the cytosol of Trypanosoma cruzi epimastigote forms. Like mammalian CaM KII, TcCaM K has a broad substrate specificity and a similar subunit composition. Western blot analysis revealed that this TcCaM K possesses two subunits of 50 and 60 kDa, which exhibited autophosphorylating activity. A panel of monoclonal and polyclonal antibodies raised against rat brain CaM KII could also recognize TcCaM K. However, experimental evidence suggests a different conformational arrangement of the TcCaM K subunits. Like its mammalian counterpart, two highly active autonomous, Ca(2+)-independent, states of TcCaM K can be isolated. These states, caused by high phosphate incorporation, differ only in their extent of Ca2+/CaM-dependence. About 15-20% of the autophosphorylated TcCaM K can be reverted using protein phosphatase 2A, and, consequently, its Ca(2+)-dependent activity is also partially restored. The situation is somewhat different when the enzyme is linked to the cytoskeleton, as we have previously shown. The membrane-bound form is present only in the native form. Activation increases its protein kinase activity from 5- to 14-fold. In this study, we provide evidence of another form of TcCaM K present in soluble fractions of the parasite that can be isolated in autonomous states. Our results suggest that autophosphorylation of membrane-bound TcCaM K may be responsible for kinase release in a Ca2+/CaM-independent state. These properties of TcCaM K may play an important role in regulating Ca(2+)-dependent processes in the parasite.
Collapse
Affiliation(s)
- S Ogueta
- Instituto de Investigaciones en Ingeniería Genética y Biología, Molecular (INGEBI, CONICET), Buenos Aires, Argentina
| | | | | |
Collapse
|
39
|
Felibertt P, Bermúdez R, Cervino V, Dawidowicz K, Dagger F, Proverbio T, Marín R, Benaim G. Ouabain-sensitive Na+,K(+)-ATPase in the plasma membrane of Leishmania mexicana. Mol Biochem Parasitol 1995; 74:179-87. [PMID: 8719159 DOI: 10.1016/0166-6851(95)02497-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The mechanism responsible for the regulation of intracellular Na+ and K+ concentrations in trypanosomatids is unknown. In higher eukaryotes a ouabain-sensitive Na+,K(+)-ATPase located in the plasma membrane is the main mechanism for the regulation of the intracellular concentrations of Na+ and K+, while in trypanosomatids there are conflicting evidences about the existence of this type of ATPase. By the use of a highly enriched plasma membrane fraction, we showed that an ouabain-sensitive Na+,K(+)-ATPase is present in L. mexicana. The affinity of the enzyme for Na+ and K+ is similar to that reported for the mammalian Na+,K(+)-ATPase, showing also the same kinetic parameters regarding the relative concentration of those cations that give the optimal activity. Vanadate (10 microM) fully inhibits the ATPase activity, suggesting that the enzyme belongs to the P-type family of ionic pumps. The enzyme is sensitive to ouabain and other cardiac glycosides. These cardiac glycosides do not show any appreciable effect on the higher Mg(2+)-ATPase activity present in the same preparation. By the use of [3H]ouabain, we also show in this report that the binding of the inhibitor to the enzyme was specific. Taken together, these results demonstrate that an ouabain-sensitive Na+,K(+)-ATPase is present in the plasma membrane of Leishmania mexicana. Therefore, this Na+,K(+)-ATPase should participate in the intracellular regulation of these cations in Leishmania.
Collapse
Affiliation(s)
- P Felibertt
- Centro de Biología Celular, Facultad de Ciencias, Universidad Central de Venezuela, Caracas
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Benguría A, Martín-Nieto J, Benaim G, Villalobo A. Regulatory interaction between calmodulin and the epidermal growth factor receptor. Ann N Y Acad Sci 1995; 766:472-6. [PMID: 7486695 DOI: 10.1111/j.1749-6632.1995.tb26698.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- A Benguría
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | | | | | | |
Collapse
|
41
|
Benaim G, Moreno SN, Hutchinson G, Cervino V, Hermoso T, Romero PJ, Ruiz F, de Souza W, Docampo R. Characterization of the plasma-membrane calcium pump from Trypanosoma cruzi. Biochem J 1995; 306 ( Pt 1):299-303. [PMID: 7532400 PMCID: PMC1136516 DOI: 10.1042/bj3060299] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Despite previous reports [McLaughlin (1985) Mol. Biochem. Parasitol. 15, 189-201; Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Mazumder, Mukherjee, Ghosh, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] suggesting that the plasma-membrane Ca(2+)-ATPases of different trypanosomatids differ from the Ca2+ pumps present in mammalian cells, Trypanosoma cruzi plasma-membrane Ca(2+)-ATPase shares several characteristics with the Ca2+ pumps present in other systems. This enzyme could be partially purified from epimastigote plasma-membrane vesicles using calmodulin-agarose affinity chromatography. The activity of the partially purified enzyme was stimulated by T. cruzi or bovine brain calmodulin. In addition, the enzyme cross-reacted with antiserum and monoclonal antibody 5F10 raised against human red-blood-cell Ca(2+)-ATPase, has a molecular mass of 140 kDa and forms Ca(2+)-dependent hydroxylamine-sensitive phosphorylated intermediates. These results, together with its high sensitivity to vanadate, indicate that this enzyme belongs to the P-type class of ionic pumps.
Collapse
Affiliation(s)
- G Benaim
- Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign 61801
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Benaim G, Cervino V, Lopez-Estraño C, Weitzman C. Ethanol stimulates the plasma membrane calcium pump from human erythrocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1195:141-8. [PMID: 7918556 DOI: 10.1016/0005-2736(94)90020-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The plasma membrane Ca(2+)-ATPase from human erythrocytes can be stimulated by different treatments such as addition of calmodulin or acidic phospholipids and controlled proteolysis. In this report we show that short chain alkyl alcohols also stimulated this enzyme. At 5% (v/v) ethanol, the maximal velocity of the enzyme was about 2.4-fold higher than in the control, and thus, was also higher than the maximal velocity obtained in the presence of calmodulin (about 2-fold). When ethanol and calmodulin were present simultaneously, the stimulatory effect was additive (3.4-fold stimulation). On the other hand, the stimulatory effect of ethanol was preserved after treatment of the enzyme with trypsin to stimulate the Ca(2+)-ATPase and render it independent of calmodulin, thus suggesting that the interaction of ethanol and calmodulin with the Ca(2+)-ATPase occurred through a different mechanism. Other short chain alkyl alcohols (methanol, n-propanol and n-butanol) stimulated the Ca(2+)-ATPase activity to the same extent than ethanol but with different efficacy. Thus, the larger the carbon number, the lower the concentration needed to get the same maximal stimulation. Ethanol also increased the affinity of the enzyme for ATP to a larger extent and additively, when compared to calmodulin. All the effects of ethanol mentioned above were identically observed on the membrane-bound enzyme (i.e., erythrocyte ghosts) ruling out any effect of the alcohols attributable to the solubilized purified enzyme. Furthermore, Ca2+ transport by inside-out vesicles was also stimulated by ethanol, showing both the same concentration-dependence as the Ca(2+)-ATPase activity and the additive effect observed when calmodulin was also present. The stimulatory effect of ethanol was significant at pharmacological concentrations, thus suggesting potential implications of toxicological relevance.
Collapse
Affiliation(s)
- G Benaim
- Centro de Biologia Celular, Facultad de Ciencias, Universidad Central de Venezuela, Caracas
| | | | | | | |
Collapse
|
43
|
Yakubu MA, Majumder S, Kierszenbaum F. Changes in Trypanosoma cruzi infectivity by treatments that affect calcium ion levels. Mol Biochem Parasitol 1994; 66:119-25. [PMID: 7984174 DOI: 10.1016/0166-6851(94)90042-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The possible role of the intracellular Ca2+ level in the regulation of Trypanosoma cruzi infectivity was explored by measuring the capacity of trypomastigote forms of this organism to invade mammalian host cells after treatments which decrease or elevate cytoplasmic Ca2+. Parasites loaded with either bis-(o-aminophenoxy)-ethane-N,N,N',N' tetraacetic acid (BAPTA) or 2-([2-bis(carboxymethyl)-amino-5-methylphenoxy]methyl)-6-nethoxy-8 - bis(carboxymethyl)aminoquinoline (Quin-2) to chelate Ca2+ displayed significantly decreased infectivity. This effect was denoted by reductions in both the proportion of rat heart myoblasts invaded by the parasite in vitro and the number of trypanosomes penetrating these host cells, the extents of which were BAPTA or Quin-2 concentration dependent. Consistent with these observations, inhibitory effects were also recorded when the parasite was pretreated with the calmodulin-binding phenothiazines trifluoperazine and chlorpromazine or with felodipine, a chemically different type of calmodulin antagonist, for as little as 5 min. In contrast, pretreatment with the Ca2+ ionophore ionomycin, which elevated Ca2+ levels in T. cruzi, significantly enhanced the infective capacity of the parasite. These results point to the existence of a Ca(2+)-dependent mechanism that regulates the invasive capacity of T. cruzi.
Collapse
Affiliation(s)
- M A Yakubu
- Department of Microbiology, Michigan State University, East Lansing 48824
| | | | | |
Collapse
|
44
|
Ogueta SB, Solari A, Téllez-Iñón MT. Trypanosoma cruzi epimastigote forms possess a Ca(2+)-calmodulin dependent protein kinase. FEBS Lett 1994; 337:293-7. [PMID: 8293818 DOI: 10.1016/0014-5793(94)80212-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Trypanosoma cruzi epimastigote forms showed a tightly bound Ca(2+)-calmodulin-dependent protein kinase activity, which could be partially extracted from membranes and axonemes. The enzyme is constituted by subunits which were autophosphorylated in the absence of exogenous substrates. An antibody against CaM kinase II recognized a Ca(2+)- or Ca(2+)-CaM-dependent conformational epitope in these fractions. The detected bands were of molecular weights similar to the alpha and beta subunits of the corresponding bovine brain enzyme (60 and 50 kDa). Studies using [125I]CaM revealed the presence of a CaM-binding domain. These experiments confirm that the parasite possesses a particulate CaM kinase with characteristics similar to the bovine brain enzyme.
Collapse
Affiliation(s)
- S B Ogueta
- Instituto de Investigaciones en Ingenieria Genética y Biologia Molecular (INGEBI) UBA, Argentina
| | | | | |
Collapse
|
45
|
Docampo R, Moreno SN, Vercesi AE. Effect of thapsigargin on calcium homeostasis in Trypanosoma cruzi trypomastigotes and epimastigotes. Mol Biochem Parasitol 1993; 59:305-13. [PMID: 8341327 DOI: 10.1016/0166-6851(93)90228-p] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
By using the fluorescent calcium indicator fura-2, it was found that the concentration of free Ca2+ in the cytoplasm of Trypanosoma cruzi trypomastigotes incubated in the presence or absence of external calcium was maintained at very low levels (10-20 nM). When trypomastigotes were incubated in the presence of succinate and ATP and permeabilized with digitonin, they lowered the medium calcium concentration to a submicromolar level. In the presence of 1 microM FCCP the initial rate of Ca2+ sequestration by these permeabilized cells was very slow. When succinate alone was present, the initial rate of Ca2+ accumulation was slower than with ATP plus succinate, and the calcium set point was about 0.6 microM. The succinate dependence and FCCP sensitivity of the later Ca2+ uptake indicate that it may be exerted by the mitochondria. High concentrations of the tumor promoter thapsigargin slightly increased cytosolic Ca2+ in the presence of extracellular Ca2+ but had no effect on the FCCP- and oligomycin/antimycin A-insensitive Ca2+ pool. In addition, when used at those concentrations (4-20 microM), thapsigargin was shown to release Ca2+ from the mitochondria and to decrease the inner mitochondrial membrane potential of trypomastigotes and epimastigotes as measured using safranine O. Despite the presence of inositol phosphates as determined by [3H]inositol incorporation, no IP3-sensitive Ca2+ release could be detected in trypomastigotes.
Collapse
Affiliation(s)
- R Docampo
- Department of Veterinary Pathobiology, University of Illinois, Urbana 61801
| | | | | |
Collapse
|
46
|
Docampo R, Gadelha FR, Moreno SN, Benaim G, Hoffmann ME, Vercesi AE. Disruption of Ca2+ homeostasis in Trypanosoma cruzi by crystal violet. J Eukaryot Microbiol 1993; 40:311-6. [PMID: 8508168 DOI: 10.1111/j.1550-7408.1993.tb04921.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have demonstrated previously that crystal violet induces a rapid, dose-related collapse of the inner mitochondrial membrane potential of Trypanosoma cruzi epimastigotes. In this work, we show that crystal violet-induced dissipation of the membrane potential was accompanied by an efflux of Ca2+ from the mitochondria. In addition, crystal violet inhibited the ATP-dependent, oligomycin-, and antimycin A-insensitive Ca2+ uptake by digitonin-permeabilized epimastigotes. Crystal violet also induced Ca2+ release from the mitochondria and endoplasmic reticulum of digitonin-permeabilized trypomastigotes. Furthermore, crystal violet inhibited Ca2+ uptake and the (Ca(2+)-Mg2+)-ATPase of a highly enriched plasma membrane fraction of epimastigotes, thus indicating an inhibition of other calcium transport mechanisms of the cells. Disruption of Ca2+ homeostasis by crystal violet may be a key process leading to trypanosome cell injury by this drug.
Collapse
Affiliation(s)
- R Docampo
- Department of Veterinary Pathobiology, University of Illinois, Urbana 61801
| | | | | | | | | | | |
Collapse
|
47
|
Krassner SM, Chang J, Pak S, Luc KO, Granger B. Absence of transitory [Ca2+]i flux during early in vitro metacyclogenesis of Trypanosoma cruzi. J Eukaryot Microbiol 1993; 40:224-30. [PMID: 8461896 DOI: 10.1111/j.1550-7408.1993.tb04907.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The phorbol ester TPA (phorbol 12-myristate 13-acetate) substitutes for CO2 as an agonist for transforming Trypanosoma cruzi epimastigotes to the metacyclic trypomastigote stage in a starvation medium consisting of phosphate buffered saline + 10 mM proline, 10 mM sodium acetate and 0.035% NaHCO3. Since TPA is thought to stimulate protein kinase C by mimicking the activity of the secondary messenger diacylglycerol, the above result suggested that T. cruzi metacyclogenesis could be activated by a Ca(2+)-dependent protein kinase C signal induction pathway. Accordingly, cytosolic calcium flux ([Ca2+]i) in epimastigotes, activated with 5% CO2 or TPA (10(-7) M), was measured with the Ca2+ molecular probe, fluo-3AM. In addition, [Ca2+]i was measured in cells incubated with putative metacyclogenic agonists (e.g. proline, glutamate, bioamines, ionophores and catecholamines). None of the compounds studies, except for EGTA, affected cytosolic Ca2+ levels. Control assays with 11 microM thapsigargin, which mobilizes noncytoplasmic Ca2+ stores by inhibiting endoplasmic reticulum Ca(2+)-ATPase, validated our fluorometric assay procedure. Although thapsigargin significantly increases cytoplasmic Ca2+ fluorescence, it has no effect on transformation. The protein kinase C inhibitors staurosporine, H-7 and HA 1004 were tested for their effect on T. cruzi metacyclogenesis. Low concentrations of staurosporine and HA 1004 significantly elevated Peru strain transformation while H-7 had no effect on Peru strain metacyclogenesis. Inhibitor H-7 did significantly depress CL transformation. The results indicate that induction of T. cruzi metacyclic trypomastigote formation by CO2 and TPA is not accompanied by changes in cytosolic Ca2+ and do not provide supporting evidence for participation of a protein kinase C-mediated phosphoinositide cascade in metacyclogenesis.
Collapse
Affiliation(s)
- S M Krassner
- Department of Developmental and Cell Biology, University of California, Irvine 92717
| | | | | | | | | |
Collapse
|
48
|
Zilberstein D. Transport of nutrients and ions across membranes of trypanosomatid parasites. ADVANCES IN PARASITOLOGY 1993; 32:261-91. [PMID: 8237616 DOI: 10.1016/s0065-308x(08)60209-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- D Zilberstein
- Department of Biology, Technion-Israel Institute of Technology, Haifa
| |
Collapse
|
49
|
Vercesi AE, Docampo R, Moreno SN. Energization-dependent Ca2+ accumulation in Trypanosoma brucei bloodstream and procyclic trypomastigotes mitochondria. Mol Biochem Parasitol 1992; 56:251-7. [PMID: 1484549 DOI: 10.1016/0166-6851(92)90174-i] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The permeabilization of Trypanosoma brucei procyclic and bloodstream trypomastigotes with digitonin permitted the quantitative estimation of a mitochondrial membrane potential of the order of 130-140 mV, in both forms, using safranine O. Dependence on substrate oxidation and response of the procyclic mitochondrial membrane potential to phosphate, FCCP, valinomycin, and Ca2+ indicate that these mitochondria behave similarly to vertebrate mitochondria regarding the properties of their electrochemical proton gradient. In contrast, in bloodstream mitochondria, development of a membrane potential was independent of substrate oxidation and dependent on hydrolysis of ATP by the mitochondrial oligomycin-sensitive ATPase, as demonstrated by collapse of the membrane potential by oligomycin and its insensitivity to the respiratory chain-inhibitor antimycin A. Mitochondria of T. brucei bloodstream forms were also able to take up Ca2+ by an electrophoretic mechanism. This is the first report of the presence of a Ca2+ transport mechanism in an eukaryotic cell devoid of complete tricarboxylic acid cycle and respiratory chain, the activities of which are known to be regulated by changes in intramitochondrial calcium concentration in other cells.
Collapse
Affiliation(s)
- A E Vercesi
- Department of Veterinary Pathobiology, University of Illinois, Urbana 61801
| | | | | |
Collapse
|
50
|
Cataldi de Flombaum MA, Stoppani AO. High-affinity calcium-stimulated, magnesium-dependent adenosine triphosphatase in Trypanosoma cruzi. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1992; 103:933-7. [PMID: 1478071 DOI: 10.1016/0305-0491(92)90218-g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
1. A high-affinity (Ca2+ + Mg2+)-ATPase and a low-affinity Mg(2+)-ATPase were identified in the 105,000 g fraction from epimastigote forms of Trypanosoma cruzi, the agent of Chagas' disease (Tulahuen strain). 2. Activities were conserved after enzyme solubilization with deoxycholate. 3. The Ca(2+)-stimulated ATPase activity was (a) lower than that of the Mg(2+)-ATPase; (b) inhibited by p-chloromercurobenzoate and orthovanadate and (c) insensitive to oligomycin. 4. Optimal stimulation by Ca2+ was observed at pH 6.5-6.8 in the presence of 1 mM MgCl2 and 0.1 M KCl. 5. The Mg(2+)-ATPase was insensitive to p-chloromercurobenzoate and orthovanadate and did not require KCl for activity. 6. Kinetic analysis of the (Ca2+ + Mg2+)-ATPase yielded a half-maximal stimulating concentration of 1.1 microM for Ca2+ and a Km of 66 microM for ATP. 7. The (Ca2+ + Mg2+)-ATPase clearly differed from the Ca(2+)- or Mg(2+)-ATPases previously characterized in the same strain of T. cruzi (Frasch et al., 1978; Comp. Biochem. Physiol. 60B, 271-275).
Collapse
|