SERINE PROTEINASES IN APICOMPLEXAN PARASITES

Summary

Principal Investigator: Kami Kim
Abstract: Toxoplasma gondii and related Apicomplexan parasites including Cryptosporidium cause significant human disease particularly in AIDS patients. T. gondii and C. parvum are also category B bioterrorism agents that pose a particular threat to the immunocompromised. The Apicomplexa are named for their unique apical secretory organelles-micronemes, rhoptries and dense granules. Proteolytic processing of secretory organelle contents occurs throughout the Apicomplexa. We have characterized two subtilisin-like serine proteinases (subtilases) from T. gondii, TgSUB1 and TgSUB2. TgSUB1 localizes to the micronemes, whereas TgSUB2 is a rhoptry protein that appears to be a rhoptry protein maturase. TgSUB2 cannot be disrupted, and antisense depletion of TgSUB2 results in parasites that divide poorly, have few rhoptries, and have large aberrant cytoplasmic vesicles. In contrast, TgSUB1 disruptants are viable. We hypothesize that Toxoplasma subtilases play an essential role in the biogenesis or function of micronemes and rhoptries. We plan to test the importance of TgSUB2 using genetic methods and to characterize TgSUB2 biological substrates. Because proteinase inhibitors typically mimic substrates, identification of a natural substrate for TgSUB2 would accelerate synthesis of specific inhibitors and elucidate the role of TgSUB2 in parasite survival. We will use recombinant TgSUB2 to develop an in vitro assay for TgSUB2 activity that can be used to identify substrates and unique inhibitors of TgSUB2. Finally, we will investigate the expression of other subtilase genes present in the T. gondii genome. We hypothesize that TgSUB1 is not essential because its function is redundant with other subtilase family members. We will determine the expression pattern and localization of other subtilases in T. gondii tachyzoites and use genetic techniques to determine if they have overlapping function with TgSUB1. In addition to illuminating the function and biology of T. gondii secretory organelles, these studies will determine whether subtilases are a viable chemotherapeutic target for treatment of human infections with Apicomplexan parasites.
Funding Period: 1999-12-01 - 2011-01-31
more information: NIH RePORT

Top Publications

  1. pmc Kinetic and isotopic characterization of L-proline dehydrogenase from Mycobacterium tuberculosis
    Hector Serrano
    Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, United States
    Biochemistry 52:5009-15. 2013
  2. pmc The prodomain of Toxoplasma gondii GPI-anchored subtilase TgSUB1 mediates its targeting to micronemes
    Emily M Binder
    Department of Medicine, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
    Traffic 9:1485-96. 2008
  3. pmc Plasmodium protease ROM1 is important for proper formation of the parasitophorous vacuole
    Iset Medina Vera
    Departments of Medicine and of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
    PLoS Pathog 7:e1002197. 2011
  4. pmc Bright and stable near-infrared fluorescent protein for in vivo imaging
    Grigory S Filonov
    Department of Anatomy and Structural Biology and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, USA
    Nat Biotechnol 29:757-61. 2011
  5. pmc Improved techniques for endogenous epitope tagging and gene deletion in Toxoplasma gondii
    Rajendra Upadhya
    Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    J Microbiol Methods 85:103-13. 2011
  6. pmc Toxoplasma gondii protease TgSUB1 is required for cell surface processing of micronemal adhesive complexes and efficient adhesion of tachyzoites
    Vanessa Lagal
    Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Cell Microbiol 12:1792-808. 2010
  7. pmc Role of CpSUB1, a subtilisin-like protease, in Cryptosporidium parvum infection in vitro
    Jane W Wanyiri
    Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA 02111, USA
    Eukaryot Cell 8:470-7. 2009
  8. pmc Toxoplasma: the next 100years
    Kami Kim
    Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Microbes Infect 10:978-84. 2008
  9. pmc Stable expression of Cryptosporidium parvum glycoprotein gp40/15 in Toxoplasma gondii
    ROBERTA M O'CONNOR
    Division of Geographic Medicine and Infectious Diseases, Tufts New England Medical Center, Boston, MA, United States
    Mol Biochem Parasitol 152:149-58. 2007
  10. pmc Proteolytic processing of the Cryptosporidium glycoprotein gp40/15 by human furin and by a parasite-derived furin-like protease activity
    Jane W Wanyiri
    Division of Geographic Medicine and Infectious Diseases, Tufts New England Medical Center, 750 Washington Street, Boston, MA 02111, USA
    Infect Immun 75:184-92. 2007

Scientific Experts

  • Kami Kim
  • ROBERTA M O'CONNOR
  • Jane W Wanyiri
  • Vanessa Lagal
  • Emily M Binder
  • Hector Serrano
  • Rajendra Upadhya
  • Grigory S Filonov
  • Iset Medina Vera
  • Honorine D Ward
  • John S Blanchard
  • Photini Sinnis
  • Louis M Weiss
  • Vladislav V Verkhusha
  • Kiryl D Piatkevich
  • Wandy L Beatty
  • Li Min Ting
  • Jinghang Zhang
  • RUTH HOGUE-ANGELETTI
  • Dawn Chen
  • Vern B Carruthers
  • Philippa K Harris
  • Robert N Cole
  • Roberto Diez
  • Bjorn F C Kafsack
  • My Hang Huynh
  • Michael J Blackman
  • Patsharaporn Techasintana
  • Andrew G Plaut
  • Geneve Allison
  • Anne Kane
  • Jiazhou Qiu

Detail Information

Publications10

  1. pmc Kinetic and isotopic characterization of L-proline dehydrogenase from Mycobacterium tuberculosis
    Hector Serrano
    Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, United States
    Biochemistry 52:5009-15. 2013
    ..5 ± 0.7 s(-1), and this rate is subject to a primary kinetic isotope effect of 5.2. These data confirm that the overall reaction is limited by reduced flavin reoxidation in the second half-reaction. ..
  2. pmc The prodomain of Toxoplasma gondii GPI-anchored subtilase TgSUB1 mediates its targeting to micronemes
    Emily M Binder
    Department of Medicine, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
    Traffic 9:1485-96. 2008
    ..Therefore, TgSUB1 is a novel example of a GPI-anchored protein in T. gondii that bypasses the GPI-dependent surface trafficking pathway to traffic to micronemes, specialized regulated secretory organelles...
  3. pmc Plasmodium protease ROM1 is important for proper formation of the parasitophorous vacuole
    Iset Medina Vera
    Departments of Medicine and of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
    PLoS Pathog 7:e1002197. 2011
    ..We propose a novel function for PyROM1 as a protease that promotes proper PV modification to allow parasite development and replication in a suitable environment within the mammalian host...
  4. pmc Bright and stable near-infrared fluorescent protein for in vivo imaging
    Grigory S Filonov
    Department of Anatomy and Structural Biology and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, USA
    Nat Biotechnol 29:757-61. 2011
    ..Compared with far-red GFP-like proteins, iRFP has a substantially higher signal-to-background ratio in a mouse model due to its infrared-shifted spectra...
  5. pmc Improved techniques for endogenous epitope tagging and gene deletion in Toxoplasma gondii
    Rajendra Upadhya
    Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    J Microbiol Methods 85:103-13. 2011
    ..gondii UPRT gene locus as a test case. The methods described in this paper represent an improved strategy for efficient epitope tagging and gene disruptions in T. gondii...
  6. pmc Toxoplasma gondii protease TgSUB1 is required for cell surface processing of micronemal adhesive complexes and efficient adhesion of tachyzoites
    Vanessa Lagal
    Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Cell Microbiol 12:1792-808. 2010
    ..sub1 and Δsub1::ΔGPISUB1 parasites are also less virulent in mice. Thus TgSUB1 is involved in micronemal protein processing and regulation of adhesive properties of macromolecular adhesive complexes involved in host cell invasion...
  7. pmc Role of CpSUB1, a subtilisin-like protease, in Cryptosporidium parvum infection in vitro
    Jane W Wanyiri
    Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA 02111, USA
    Eukaryot Cell 8:470-7. 2009
    ..parvum infection of HCT-8 cells. These studies indicate that CpSUB1 plays a significant role in infection of host cells by the parasite and suggest that this enzyme may serve as a target for intervention...
  8. pmc Toxoplasma: the next 100years
    Kami Kim
    Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Microbes Infect 10:978-84. 2008
    ..This review addresses recent advances in our understanding of the developmental biology and host-pathogen relationships of T. gondii...
  9. pmc Stable expression of Cryptosporidium parvum glycoprotein gp40/15 in Toxoplasma gondii
    ROBERTA M O'CONNOR
    Division of Geographic Medicine and Infectious Diseases, Tufts New England Medical Center, Boston, MA, United States
    Mol Biochem Parasitol 152:149-58. 2007
    ..The ability to express and isolate appropriately glycosylated Cryptosporidium glycoproteins will enable further investigations into host-parasite interactions of this important pathogen...
  10. pmc Proteolytic processing of the Cryptosporidium glycoprotein gp40/15 by human furin and by a parasite-derived furin-like protease activity
    Jane W Wanyiri
    Division of Geographic Medicine and Infectious Diseases, Tufts New England Medical Center, 750 Washington Street, Boston, MA 02111, USA
    Infect Immun 75:184-92. 2007
    ..The furin inhibitor Dec-RVKR-cmk decreased C. parvum infection of HCT-8 cells, suggesting that a furin-like protease activity may be involved in mediating host-parasite interactions...