This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Welter, B. H.
Right arrow Articles by Temesvari, L. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Welter, B. H.
Right arrow Articles by Temesvari, L. A.

 Previous Article  |  Next Article 

Eukaryotic Cell, July 2009, p. 1014-1026, Vol. 8, No. 7
1535-9778/09/$08.00+0     doi:10.1128/EC.00030-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Overexpression of a Mutant Form of EhRabA, a Unique Rab GTPase of Entamoeba histolytica, Alters Endoplasmic Reticulum Morphology and Localization of the Gal/GalNAc Adherence Lectin{triangledown}

B. H. Welter and L. A. Temesvari*

Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634

Received 21 January 2009/ Accepted 7 April 2009

Entamoeba histolytica is a protozoan parasite that causes amoebic dysentery and liver abscess. Vesicle trafficking events, such as phagocytosis and delivery of plasma membrane proteins, have been implicated in pathogenicity. Rab GTPases are proteins whose primary function is to regulate vesicle trafficking; therefore, understanding the function of Rabs in this organism may provide insight into virulence. E. histolytica possesses a number of unique Rabs that exhibit limited homology to host Rabs. In this study we examined the function of one such Rab, EhRabA, by characterizing a mutant overexpressing a constitutively GTP-bound version of the protein. Overexpression of mutant EhRabA resulted in decreased adhesion to and phagocytosis of human red blood cells and in the appearance of large tubular organelles that could be stained with endoplasmic reticulum (ER)-specific but not Golgi complex-specific antibodies. Consistent with the adhesion defect, two subunits of a cell surface adhesin, the galactose/N-acetylgalactosamine lectin, were mislocalized to the novel organelle. A cysteine protease, EhCP2, was also localized to the ER-like compartment in the mutant; however, the localization of two additional cell surface proteins, Igl and SREHP, remained unchanged in the mutant. The phenotype of the mutant could be recapitulated by treatment with brefeldin A, a cellular toxin that disrupts ER-to-Golgi apparatus vesicle traffic. This suggests that EhRabA influences vesicle trafficking pathways that are also sensitive to brefeldin A. Together, the data indicate that EhRabA directly or indirectly influences the morphology of secretory organelles and regulates trafficking of a subset of secretory proteins in E. histolytica.

* Corresponding author. Mailing address: Dept. of Biological Sciences, 132 Long Hall, Clemson University, Clemson, SC 29634. Phone: (864) 656-6387. Fax: (864) 656-0435. E-mail: LTEMESV{at}clemson.edu

{triangledown} Published ahead of print on 17 April 2009.

Eukaryotic Cell, July 2009, p. 1014-1026, Vol. 8, No. 7
1535-9778/09/$08.00+0     doi:10.1128/EC.00030-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2010 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»