Evidence of a Continuous Endoplasmic Reticulum in the Protozoan Parasite
            <i>Entamoeba histolytica</i>

Teixeira, José E.; Huston, Christopher D.

doi:10.1128/ec.00007-08

Cited by 37 publications

(38 citation statements)

References 20 publications

(22 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The scFv reagent worked well for immunofluorescence microscopy, and it stained a reticular network that was enriched near the cell membrane and was consistent with a previously described E. histolytica ER compartment (Fig. 1B) (50). The calreticulin staining colocalized with staining of the resident ER protein BiP.…”

Section: Resultsmentioning

confidence: 67%

Entamoeba histolytica Cell Surface Calreticulin Binds Human C1q and Functions in Amebic Phagocytosis of Host Cells

et al. 2012

Self Cite

View full text Add to dashboard Cite

ABSTRACTPhagocytosis of host cells is characteristic of tissue invasion by the intestinal amebaEntamoeba histolytica, which causes amebic dysentery and liver abscesses.Entamoeba histolyticainduces host cell apoptosis and uses ligands, including C1q, on apoptotic cells to engulf them. Two mass spectrometry analyses identified calreticulin in amebic phagosome preparations, and, in addition to its function as an endoplasmic reticulum chaperone, calreticulin is believed to be the macrophage receptor for C1q. The purpose of this study was to determine if calreticulin functions as anE. histolyticaC1q receptor during phagocytosis of host cells. Calreticulin was localized to the surface ofE. histolyticaduring interaction with both Jurkat lymphocytes and erythrocytes and was present in over 75% of phagocytic cups during amebic erythrophagocytosis. Presence of calreticulin on the cell surface was further demonstrated using a method that selectively biotinylated cell surface proteins and by flow cytometry using trophozoites overexpressing epitope-tagged calreticulin. Regulated overexpression of calreticulin increasedE. histolytica's ability to phagocytose apoptotic lymphocytes and calcium ionophore-treated erythrocytes but had no effect on amebic adherence to or destruction of cell monolayers or surface expression of the GalNAc lectin and serine-richE. histolyticaprotein (SREHP) receptors. Finally,E. histolyticacalreticulin bound specifically to apoptotic lymphocytes and to human C1q. Collectively, these data implicate cell surface calreticulin as a receptor for C1q duringE. histolyticaphagocytosis of host cells.

show abstract

Section: Resultsmentioning

confidence: 67%

Entamoeba histolytica Cell Surface Calreticulin Binds Human C1q and Functions in Amebic Phagocytosis of Host Cells

et al. 2012

Self Cite

View full text Add to dashboard Cite

show abstract

“…An ER-like structure that continuously distributes from nucleus to cytoplasm has been recently identified in Entamoeba (43). We hypothesized that the perinuclear localization of EhCP4 might be associated with the ER structure.…”

Section: Expression and Localization Of Endogenous Ehcp4 In E Histolmentioning

confidence: 99%

A Novel Entamoeba histolytica Cysteine Proteinase, EhCP4, Is Key for Invasive Amebiasis and a Therapeutic Target

Nora

Schneider

et al. 2010

Journal of Biological Chemistry

View full text Add to dashboard Cite

Entamoeba histolytica cysteine proteinases (EhCPs) play a key role in disrupting the colonic epithelial barrier and the innate host immune response during invasion of E. histolytica, the protozoan cause of human amebiasis. EhCPs are encoded by 50 genes, of which ehcp4 (ehcp-a4) is the most up-regulated during invasion and colonization in a mouse cecal model of amebiasis. Up-regulation of ehcp4 in vivo correlated with our finding that co-culture of E. histolytica trophozoites with mucin-producing T84 cells increased ehcp4 expression up to 6-fold. We have expressed recombinant EhCP4, which was autocatalytically activated at acidic pH but had highest proteolytic activity at neutral pH. In contrast to the other amebic cysteine proteinases characterized so far, which have a preference for arginine in the P2 position, EhCP4 displayed a unique preference for valine and isoleucine at P2. This preference was confirmed by homology modeling, which revealed a shallow, hydrophobic S2 pocket. Endogenous EhCP4 localized to cytoplasmic vesicles, the nuclear region, and perinuclear endoplasmic reticulum (ER). Following co-culture with colonic cells, EhCP4 appeared in acidic vesicles and was released extracellularly. A specific vinyl sulfone inhibitor, WRR605, synthesized based on the substrate specificity of EhCP4, inhibited the recombinant enzyme in vitro and significantly reduced parasite burden and inflammation in the mouse cecal model. The unique expression pattern, localization, and biochemical properties of EhCP4 could be exploited as a potential target for drug design.

show abstract

“…Typical eukaryotic cytoplasmic organelles have not been observed in this organism. However, the functional equivalents of a Golgi network and an endoplasmic reticulum are reported to be present (3,26). Entamoeba also contains a genomeless variant of mitochondria, termed mitosomes (17).…”

mentioning

confidence: 99%

Identification and Partial Characterization of a Dynamin-Like Protein, EhDLP1, from the Protist Parasite Entamoeba histolytica

et al. 2010

View full text Add to dashboard Cite

The dynamin superfamily of proteins includes a large repertoire of evolutionarily conserved GTPases that interact with different subcellular organelle membranes in eukaryotes. Dynamins are thought to participate in a number of cellular processes involving membrane remodeling and scission. Dynamin-like proteins (DLPs) form a subfamily of this vast class and play important roles in cellular processes, such as mitochondrial fission, cytokinesis, and endocytosis. In the present study, a gene encoding a dynamin-like protein (EhDLP1) from the protist parasite Entamoeba histolytica was identified and the protein was partially characterized using a combination of in silico, biochemical, and imaging methods. The protein was capable of GTP binding and hydrolysis, lipid binding, and oligomerization. Immunofluorescence studies showed the protein to be associated with the nuclear membrane. A mutant of EhDLP1 lacking GTP binding and hydrolyzing activities did not associate with the nuclear membrane. The results suggest a nucleus-associated function for EhDLP1.

show abstract

Evidence of a Continuous Endoplasmic Reticulum in the Protozoan Parasite Entamoeba histolytica

Cited by 37 publications

References 20 publications

Entamoeba histolytica Cell Surface Calreticulin Binds Human C1q and Functions in Amebic Phagocytosis of Host Cells

Entamoeba histolytica Cell Surface Calreticulin Binds Human C1q and Functions in Amebic Phagocytosis of Host Cells

A Novel Entamoeba histolytica Cysteine Proteinase, EhCP4, Is Key for Invasive Amebiasis and a Therapeutic Target

Identification and Partial Characterization of a Dynamin-Like Protein, EhDLP1, from the Protist Parasite Entamoeba histolytica

Contact Info

Product

Resources

About