Proteomic Analysis of the Acidocalcisome, an Organelle Conserved from Bacteria to Human Cells
Acidocalcisomes are acidic organelles conserved from bacteria to human cells that are rich in polyphosphate, a polymer of orthophosphate units linked by high-energy phospho-anyhidride bonds. We found here that acidocalcisomes from Trypanosoma brucei, belonging to the group of organisms that produces African sleeping sickness and nagana, are rich in pumps, channels, and transporters involved in phosphate and cation homeostasis, and calcium signaling. Proteomic analysis of acidocalcisome fractions and expression of genes with epitope tags validated the presence of a number of novel transporters, and RNA interference demonstrated the essentiality of these organelles.
Vyšlo v časopise:
Proteomic Analysis of the Acidocalcisome, an Organelle Conserved from Bacteria to Human Cells. PLoS Pathog 10(12): e32767. doi:10.1371/journal.ppat.1004555
Kategorie:
Research Article
prolekare.web.journal.doi_sk:
https://doi.org/10.1371/journal.ppat.1004555
Souhrn
Acidocalcisomes are acidic organelles conserved from bacteria to human cells that are rich in polyphosphate, a polymer of orthophosphate units linked by high-energy phospho-anyhidride bonds. We found here that acidocalcisomes from Trypanosoma brucei, belonging to the group of organisms that produces African sleeping sickness and nagana, are rich in pumps, channels, and transporters involved in phosphate and cation homeostasis, and calcium signaling. Proteomic analysis of acidocalcisome fractions and expression of genes with epitope tags validated the presence of a number of novel transporters, and RNA interference demonstrated the essentiality of these organelles.
Zdroje
1. BabesV (1895) Beobachtungen über die metachromatischen körperchen, sporenbildung, verzwiegung, kolben- und kapsel-bildung pathogener bakterien. Zentralbl Bakteriol Parasitenkd Infektionskr Hyg 20: 412–420.
2. MeyerA (1904) Orientirende untersuchungen uber verbreitung, morphologie und chemie des volutins. Bot Zeit 62: 113–152.
3. WiameJM (1947) Etude d'une substance polyphosphoree, basophile et metachromatique chez les levures. Biochim Biophys acta 1: 234–255.
4. RaoNN, Gomez-GarciaMR, KornbergA (2009) Inorganic polyphosphate: essential for growth and survival. Annu Rev Biochem 78: 605–647.
5. DocampoR, de SouzaW, MirandaK, RohloffP, MorenoSN (2005) Acidocalcisomes - conserved from bacteria to man. Nat Rev Microbiol 3: 251–261.
6. SeufferheldM, LeaCR, VieiraM, OldfieldE, DocampoR (2004) The H+-pyrophosphatase of Rhodospirillum rubrum is predominantly located in polyphosphate-rich acidocalcisomes. J Biol Chem 279: 51193–51202.
7. SeufferheldM, VieiraMC, RuizFA, RodriguesCO, MorenoSN, et al. (2003) Identification of organelles in bacteria similar to acidocalcisomes of unicellular eukaryotes. J Biol Chem 278: 29971–29978.
8. VercesiAE, MorenoSN, DocampoR (1994) Ca2+/H+ exchange in acidic vacuoles of Trypanosoma brucei. Biochem J 304: 227–233.
9. DocampoR, ScottDA, VercesiAE, MorenoSN (1995) Intracellular Ca2+ storage in acidocalcisomes of Trypanosoma cruzi. Biochem J 310: 1005–1012.
10. RodriguesCO, ScottDA, DocampoR (1999) Presence of a vacuolar H+-pyrophosphatase in promastigotes of Leishmania donovani and its localization to a different compartment from the vacuolar H+-ATPase. Biochem J 340: 759–766.
11. MorenoSN, ZhongL (1996) Acidocalcisomes in Toxoplasma gondii tachyzoites. Biochem J 313: 655–659.
12. MarchesiniN, LuoS, RodriguesCO, MorenoSN, DocampoR (2000) Acidocalcisomes and a vacuolar H+-pyrophosphatase in malaria parasites. Biochem J 347: 243–253.
13. Soares MedeirosLC, GomesF, MacielLR, SeabraSH, DocampoR, et al. (2011) Volutin granules of Eimeria parasites are acidic compartments and have physiological and structural characteristics similar to acidocalcisomes. J Eukaryot Microbiol 58: 416–423.
14. MarchesiniN, RuizFA, VieiraM, DocampoR (2002) Acidocalcisomes are functionally linked to the contractile vacuole of Dictyostelium discoideum. J Biol Chem 277: 8146–8153.
15. FranzenAJ, CunhaMM, MirandaK, HentschelJ, PlattnerH, et al. (2008) Ultrastructural characterization of melanosomes of the human pathogenic fungus Fonsecaea pedrosoi. J Struct Biol 162: 75–84.
16. RuizFA, MarchesiniN, SeufferheldM, Govindjee, DocampoR (2001) The polyphosphate bodies of Chlamydomonas reinhardtii possess a proton-pumping pyrophosphatase and are similar to acidocalcisomes. J Biol Chem 276: 46196–46203.
17. YagisawaF, NishidaK, YoshidaM, OhnumaM, ShimadaT, et al. (2009) Identification of novel proteins in isolated polyphosphate vacuoles in the primitive red alga Cyanidioschyzon merolae. Plant J 60: 882–893.
18. MottaLS, RamosIB, GomesFM, de SouzaW, ChampagneDE, et al. (2009) Proton-pyrophosphatase and polyphosphate in acidocalcisome-like vesicles from oocytes and eggs of Periplaneta americana. Insect Biochem Mol Biol 39: 198–206.
19. RamosI, GomesF, KoellerCM, SaitoK, HeiseN, et al. (2011) Acidocalcisomes as calcium- and polyphosphate-storage compartments during embryogenesis of the insect Rhodnius prolixus Stahl. PLoS One 6: e27276.
20. RamosIB, MirandaK, PaceDA, VerbistKC, LinFY, et al. (2010) Calcium- and polyphosphate-containing acidic granules of sea urchin eggs are similar to acidocalcisomes, but are not the targets for NAADP. Biochem J 429: 485–495.
21. RamosIB, MirandaK, UlrichP, IngramP, LeFurgeyA, et al. (2010) Calcium- and polyphosphate-containing acidocalcisomes in chicken egg yolk. Biol Cell 102: 421–434.
22. RuizFA, LeaCR, OldfieldE, DocampoR (2004) Human platelet dense granules contain polyphosphate and are similar to acidocalcisomes of bacteria and unicellular eukaryotes. J Biol Chem 279: 44250–44257.
23. Moreno-SanchezD, Hernandez-RuizL, RuizFA, DocampoR (2012) Polyphosphate is a novel pro-inflammatory regulator of mast cells and is located in acidocalcisomes. J Biol Chem 287: 28435–28444.
24. RodriguesCO, ScottDA, DocampoR (1999) Characterization of a vacuolar pyrophosphatase in Trypanosoma brucei and its localization to acidocalcisomes. Mol Cell Biol 19: 7712–7723.
25. SaltoML, KuhlenschmidtT, KuhlenschmidtM, de LederkremerRM, DocampoR (2008) Phospholipid and glycolipid composition of acidocalcisomes of Trypanosoma cruzi. Mol Biochem Parasitol 158: 120–130.
26. ScottDA, de SouzaW, BenchimolM, ZhongL, LuHG, et al. (1998) Presence of a plant-like proton-pumping pyrophosphatase in acidocalcisomes of Trypanosoma cruzi. J Biol Chem 273: 22151–22158.
27. HuangG, BartlettPJ, ThomasAP, MorenoSN, DocampoR (2013) Acidocalcisomes of Trypanosoma brucei have an inositol 1,4,5-trisphosphate receptor that is required for growth and infectivity. Proc Natl Acad Sci U S A 110: 1887–1892.
28. LemercierG, EspiauB, RuizFA, VieiraM, LuoS, et al. (2004) A pyrophosphatase regulating polyphosphate metabolism in acidocalcisomes is essential for Trypanosoma brucei virulence in mice. J Biol Chem 279: 3420–3425.
29. LemercierG, DutoyaS, LuoS, RuizFA, RodriguesCO, et al. (2002) A vacuolar-type H+-pyrophosphatase governs maintenance of functional acidocalcisomes and growth of the insect and mammalian forms of Trypanosoma brucei. J Biol Chem 277: 37369–37376.
30. NesvizhskiiAI, KellerA, KolkerE, AebersoldR (2003) A statistical model for identifying proteins by tandem mass spectrometry. Anal Chem 75: 4646–4658.
31. WallinE, von HeijneG (1998) Genome-wide analysis of integral membrane proteins from eubacterial, archaean, and eukaryotic organisms. Protein Sci 7: 1029–1038.
32. PatelS, DocampoR (2010) Acidic calcium stores open for business: expanding the potential for intracellular Ca2+ signaling. Trends Cell Biol 20: 277–286.
33. BangsJD, UyetakeL, BrickmanMJ, BalberAE, BoothroydJC (1993) Molecular cloning and cellular localization of a BiP homologue in Trypanosoma brucei. Divergent ER retention signals in a lower eukaryote. J Cell Sci 105: 1101–1113.
34. UlrichPN, JimenezV, ParkM, MartinsVP, AtwoodJ3rd, et al. (2011) Identification of contractile vacuole proteins in Trypanosoma cruzi. PLoS One 6: e18013.
35. HashimotoM, EnomotoM, MoralesJ, KurebayashiN, SakuraiT, et al. (2013) Inositol 1,4,5-trisphosphate receptor regulates replication, differentiation, infectivity and virulence of the parasitic protist Trypanosoma cruzi. Mol Microbiol 87: 1133–1150.
36. LuoS, RohloffP, CoxJ, UyemuraSA, DocampoR (2004) Trypanosoma brucei plasma membrane-type Ca2+-ATPase 1 (TbPMC1) and 2 (TbPMC2) genes encode functional Ca2+-ATPases localized to the acidocalcisomes and plasma membrane, and essential for Ca2+ homeostasis and growth. J Biol Chem 279: 14427–14439.
37. HothornM, NeumannH, LenherrED, WehnerM, RybinV, et al. (2009) Catalytic core of a membrane-associated eukaryotic polyphosphate polymerase. Science 324: 513–516.
38. LanderN, UlrichPN, DocampoR (2013) Trypanosoma brucei vacuolar transporter chaperone 4 (TbVtc4) is an acidocalcisome polyphosphate kinase required for in vivo infection. J Biol Chem 288: 34205–34216.
39. UlrichPN, LanderN, KurupS, ReissL, BrewerJ, et al. (2014) The acidccalcisome vacuolar transporter chaperone 4 catalyzes the synthesis of polyphosphate in insect-stages of Trypanosoma brucei and T. cruzi. J Eukaryot Microbiol 61: 155–165.
40. FangJ, RohloffP, MirandaK, DocampoR (2007) Ablation of a small transmembrane protein of Trypanosoma brucei (TbVTC1) involved in the synthesis of polyphosphate alters acidocalcisome biogenesis and function, and leads to a cytokinesis defect. Biochem J 407: 161–170.
41. GomesSA, Fonseca de SouzaAL, SilvaBA, Kiffer-MoreiraT, Santos-MalletJR, et al. (2006) Trypanosoma rangeli: Differential expression of cell surface polypeptides and ecto-phosphatase activity in short and long epimastigote forms. Exp Parasitol 112: 253–262.
42. WilliamsonJ, McLarenDJ (1981) Localization of phosphatases in Trypanosoma rhodesiense. J Protozool 28: 460–467.
43. BowmanEJ, SiebersA, AltendorfK (1988) Bafilomycins: a class of inhibitors of membrane ATPases from microorganisms, animal cells, and plant cells. Proc Natl Acad Sci U S A 85: 7972–7976.
44. ScottDA, MorenoSN, DocampoR (1995) Ca2+ storage in Trypanosoma brucei: the influence of cytoplasmic pH and importance of vacuolar acidity. Biochem J 310: 789–794.
45. HeCY, HoHH, MalsamJ, ChalouniC, WestCM, et al. (2004) Golgi duplication in Trypanosoma brucei. J Cell Biol 165: 313–321.
46. TazehNN, SilvermanJS, SchwartzKJ, SevovaES, SutterwalaSS, et al. (2009) Role of AP-1 in developmentally regulated lysosomal trafficking in Trypanosoma brucei. Eukaryot Cell 8: 1352–1361.
47. CorreaAF, AndradeLR, SoaresMJ (2002) Elemental composition of acidocalcisomes of Trypanosoma cruzi bloodstream trypomastigote forms. Parasitol Res 88: 875–880.
48. MirandaK, RodriguesCO, HentchelJ, VercesiA, PlattnerH, et al. (2004) Acidocalcisomes of Phytomonas francai possess distinct morphological characteristics and contain iron. Microsc Microanal 10: 647–655.
49. MirandaK, DocampoR, GrilloO, de SouzaW (2004) Acidocalcisomes of trypanosomatids have species-specific elemental composition. Protist 155: 395–405.
50. MirandaK, DocampoR, GrilloO, FranzenA, AttiasM, et al. (2004) Dynamics of polymorphism of acidocalcisomes in Leishmania parasites. Histochem Cell Biol 121: 407–418.
51. FerellaM, NilssonD, DarbanH, RodriguesC, BontempiEJ, et al. (2008) Proteomics in Trypanosoma cruzi–localization of novel proteins to various organelles. Proteomics 8: 2735–2749.
52. DeGrasseJA, DuBoisKN, DevosD, SiegelTN, SaliA, et al. (2009) Evidence for a shared nuclear pore complex architecture that is conserved from the last common eukaryotic ancestor. Mol Cell Proteomics 8: 2119–2130.
53. LingnauA, ZuffereyR, LingnauM, RussellDG (1999) Characterization of tGLP-1, a Golgi and lysosome-associated, transmembrane glycoprotein of African trypanosomes. J Cell Sci 112 Pt 18: 3061–3070.
54. TomitoriH, KashiwagiK, AsakawaT, KakinumaY, MichaelAJ, et al. (2001) Multiple polyamine transport systems on the vacuolar membrane in yeast. Biochem J 353: 681–688.
55. VercesiAE, RodriguesCO, CatistiR, DocampoR (2000) Presence of a Na+/H+ exchanger in acidocalcisomes of Leishmania donovani and their alkalization by anti-leishmanial drugs. FEBS Lett 473: 203–206.
56. VercesiAE, DocampoR (1996) Sodium-proton exchange stimulates Ca2+ release from acidocalcisomes of Trypanosoma brucei. Biochem J 315: 265–270.
57. VercesiAE, GrijalbaMT, DocampoR (1997) Inhibition of Ca2+ release from Trypanosoma brucei acidocalcisomes by 3,5-dibutyl-4-hydroxytoluene: role of the Na+/H+ exchanger. Biochem J 328: 479–482.
58. SaadaEA, KabututuZP, LopezM, ShimogawaMM, LangousisG, et al. (2014) Insect stage-specific receptor adenylate cyclases are localized to distinct subdomains of the Trypanosoma brucei flagellar membrane. Eukaryot Cell 13: 1064–1076.
59. LiuW, ApagyiK, McLeavyL, ErsfeldK (2010) Expression and cellular localisation of calpain-like proteins in Trypanosoma brucei. Mol Biochem Parasitol 169: 20–26.
60. ChanKY, ErsfeldK (2010) The role of the Kinesin-13 family protein TbKif13-2 in flagellar length control of Trypanosoma brucei. Mol Biochem Parasitol 174: 137–140.
61. SubotaI, JulkowskaD, VincensiniL, ReegN, BuissonJ, et al. (2014) Proteomic analysis of intact flagella of procyclic Trypanosoma brucei cells identifies novel flagellar proteins with unique sub-localization and dynamics. Mol Cell Proteomics 13: 1769–1786.
62. JimenezV, DocampoR (2012) Molecular and electrophysiological characterization of a novel cation channel of Trypanosoma cruzi. PLoS Pathog 8: e1002750.
63. HuangG, FangJ, Sant'AnnaC, LiZH, WellemsDL, et al. (2011) Adaptor protein-3 (AP-3) complex mediates the biogenesis of acidocalcisomes and is essential for growth and virulence of Trypanosoma brucei. J Biol Chem 286: 36619–36630.
64. BridgesDJ, PittAR, HanrahanO, BrennanK, VoorheisHP, et al. (2008) Characterisation of the plasma membrane subproteome of bloodstream form Trypanosoma brucei. Proteomics 8: 83–99.
65. LamAK, GalioneA (2013) The endoplasmic reticulum and junctional membrane communication during calcium signaling. Biochim Biophys Acta 1833: 2542–2559.
66. HuangG, VercesiAE, DocampoR (2013) Essential regulation of cell bioenergetics in Trypanosoma brucei by the mitochondrial calcium uniporter. Nat Commun 4: 2865.
67. Girard-DiasW, AlcantaraCL, Cunha-e-SilvaN, de SouzaW, MirandaK (2012) On the ultrastructural organization of Trypanosoma cruzi using cryopreparation methods and electron tomography. Histochem Cell Biol 138: 821–831.
68. OberholzerM, LangousisG, NguyenHT, SaadaEA, ShimogawaMM, et al. (2011) Independent analysis of the flagellum surface and matrix proteomes provides insight into flagellum signaling in mammalian-infectious Trypanosoma brucei. Mol Cell Proteomics 10: M111 010538.
69. HurlimannHC, Stadler-WaibelM, WernerTP, FreimoserFM (2007) Pho91 Is a vacuolar phosphate transporter that regulates phosphate and polyphosphate metabolism in Saccharomyces cerevisiae. Mol Biol Cell 18: 4438–4445.
70. MaddyAH (1976) A critical evaluation of the analysis of membrane proteins by polyacrylamide gel electrophoresis in the presence of dodecyl sulphate. J Theor Biol 62: 315–326.
71. RigdenDJ (2008) The histidine phosphatase superfamily: structure and function. Biochem J 409: 333–348.
72. HaradaK, ItohH, KawazoeY, MiyazakiS, DoiK, et al. (2013) Polyphosphate-mediated inhibition of tartrate-resistant acid phosphatase and suppression of bone resorption of osteoclasts. PLoS One 8: e78612.
73. RuizFA, RodriguesCO, DocampoR (2001) Rapid changes in polyphosphate content within acidocalcisomes in response to cell growth, differentiation, and environmental stress in Trypanosoma cruzi. J Biol Chem 276: 26114–26121.
74. CiprianoDJ, WangY, BondS, HintonA, JefferiesKC, et al. (2008) Structure and regulation of the vacuolar ATPases. Biochim Biophys Acta 1777: 599–604.
75. VieiraM, RohloffP, LuoS, Cunha-e-SilvaNL, de SouzaW, et al. (2005) Role for a P-type H+-ATPase in the acidification of the endocytic pathway of Trypanosoma cruzi. Biochem J 392: 467–474.
76. KimSA, PunshonT, LanzirottiA, LiL, AlonsoJM, et al. (2006) Localization of iron in Arabidopsis seed requires the vacuolar membrane transporter VIT1. Science 314: 1295–1298.
77. LiL, ChenOS, McVey WardD, KaplanJ (2001) CCC1 is a transporter that mediates vacuolar iron storage in yeast. J Biol Chem 276: 29515–29519.
78. DocampoR, MorenoSN (2011) Acidocalcisomes. Cell Calcium 50: 113–119.
79. NiesDH, SilverS (1995) Ion efflux systems involved in bacterial metal resistances. J Ind Microbiol 14: 186–199.
80. WangZY, LiJY, DanscherG, DahlstromA (2002) Localization of zinc-enriched neurons in the mouse peripheral sympathetic system. Brain Res 928: 165–174.
81. MacDiarmidCW, GaitherLA, EideD (2000) Zinc transporters that regulate vacuolar zinc storage in Saccharomyces cerevisiae. EMBO J 19: 2845–2855.
82. KawachiM, KobaeY, KogawaS, MimuraT, KramerU, et al. (2012) Amino acid screening based on structural modeling identifies critical residues for the function, ion selectivity and structure of Arabidopsis MTP1. FEBS J 279: 2339–2356.
83. ChaoY, FuD (2004) Kinetic study of the antiport mechanism of an Escherichia coli zinc transporter, ZitB. J Biol Chem 279: 12043–12050.
84. BonifacinoJS, TraubLM (2003) Signals for sorting of transmembrane proteins to endosomes and lysosomes. Annu Rev Biochem 72: 395–447.
85. AdachiA, KanoF, TsuboiT, FujitaM, MaedaY, et al. (2010) Golgi-associated GSK3beta regulates the sorting process of post-Golgi membrane trafficking. J Cell Sci 123: 3215–3225.
86. CunninghamI (1977) New culture medium for maintenance of tsetse tissues and growth of trypanosomatids. J Protozool 24: 325–329.
87. WirtzE, LealS, OchattC, CrossGA (1999) A tightly regulated inducible expression system for conditional gene knock-outs and dominant-negative genetics in Trypanosoma brucei. Mol Biochem Parasitol 99: 89–101.
88. HirumiH, HirumiK (1989) Continuous cultivation of Trypanosoma brucei bloodstream forms in a medium containing a low concentration of serum protein without feeder cell layers. J Parasitol 75: 985–989.
89. OberholzerM, MorandS, KunzS, SeebeckT (2006) A vector series for rapid PCR-mediated C-terminal in situ tagging of Trypanosoma brucei genes. Mol Biochem Parasitol 145: 117–120.
90. LaCountDJ, BarrettB, DonelsonJE (2002) Trypanosoma brucei FLA1 is required for flagellum attachment and cytokinesis. J Biol Chem 277: 17580–17588.
91. EmanuelssonO, NielsenH, BrunakS, von HeijneG (2000) Predicting subcellular localization of proteins based on their N-terminal amino acid sequence. J Mol Biol 300: 1005–1016.
92. GudaC, SubramaniamS (2005) pTARGET [corrected] a new method for predicting protein subcellular localization in eukaryotes. Bioinformatics 21: 3963–3969.
93. MatsudaS, VertJP, SaigoH, UedaN, TohH, et al. (2005) A novel representation of protein sequences for prediction of subcellular location using support vector machines. Protein Sci 14: 2804–2813.
94. HortonP, ParkKJ, ObayashiT, FujitaN, HaradaH, et al. (2007) WoLF PSORT: protein localization predictor. Nucleic Acids Res 35: W585–587.
95. BendtsenJD, NielsenH, von HeijneG, BrunakS (2004) Improved prediction of signal peptides: SignalP 3.0. J Mol Biol 340: 783–795.
96. KroghA, LarssonB, von HeijneG, SonnhammerEL (2001) Predicting transmembrane protein topology with a hidden Markov model: application to complete genomes. J Mol Biol 305: 567–580.
97. TusnadyGE, SimonI (2001) The HMMTOP transmembrane topology prediction server. Bioinformatics 17: 849–850.
98. KallL, KroghA, SonnhammerEL (2005) An HMM posterior decoder for sequence feature prediction that includes homology information. Bioinformatics 21 Suppl 1: i251–257.
99. KallL, KroghA, SonnhammerEL (2007) Advantages of combined transmembrane topology and signal peptide prediction–the Phobius web server. Nucleic Acids Res 35: W429–432.
100. LanzettaPA, AlvarezLJ, ReinachPS, CandiaOA (1979) An improved assay for nanomole amounts of inorganic phosphate. Anal Biochem 100: 95–97.
101. SottocasaGL, KuylenstiernaB, ErnsterL, BergstrandA (1967) An electron-transport system associated with the outer membrane of liver mitochondria. A biochemical and morphological study. J Cell Biol 32: 415–438.
102. CannataJJ, ValleE, DocampoR, CazzuloJJ (1982) Subcellular localization of phosphoenolpyruvate carboxykinase in the trypanosomatids Trypanosoma cruzi and Crithidia fasciculata. Mol Biochem Parasitol 6: 151–160.
103. LiaoYF, LalA, MoremenKW (1996) Cloning, expression, purification, and characterization of the human broad specificity lysosomal acid alpha-mannosidase. J Biol Chem 271: 28348–28358.
Štítky
Hygiena a epidemiológia Infekčné lekárstvo LaboratóriumČlánok vyšiel v časopise
PLOS Pathogens
2014 Číslo 12
- Parazitičtí červi v terapii Crohnovy choroby a dalších zánětlivých autoimunitních onemocnění
- Očkování proti virové hemoragické horečce Ebola experimentální vakcínou rVSVDG-ZEBOV-GP
- Koronavirus hýbe světem: Víte jak se chránit a jak postupovat v případě podezření?
Najčítanejšie v tomto čísle
- Plasma Membrane-Located Purine Nucleotide Transport Proteins Are Key Components for Host Exploitation by Microsporidian Intracellular Parasites
- Emergence of MERS-CoV in the Middle East: Origins, Transmission, Treatment, and Perspectives
- Experimental Cerebral Malaria Pathogenesis—Hemodynamics at the Blood Brain Barrier
- Unique Features of HIV-1 Spread through T Cell Virological Synapses