The Cytoskeleton of Entamoeba histolytica: Structure, Function, and Regulation by Signaling Pathways

Meza, Isaura; Talamás-Rohana, Patricia; Vargas, Miguel

doi:10.1016/j.arcmed.2005.09.008

Cited by 59 publications

(50 citation statements)

References 75 publications

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“…In order to invade and survive in host tissues, E. histolytica trophozoites rely on a highly dynamic cytoskeleton to perform such processes as phagocytosis, motility, or adhesion that are required for the pathogenesis of E. histolytica (23). Various components of the cytoskeleton have been identified in E. histolytica (37), and a number of proteins have been shown to bind actin, including myosin IB (56), calcium binding protein 1 (46), and the actin binding protein ABP-120 (55). In a wide variety of eukaryotic organisms, LIM domain-containing proteins have been shown to interact directly or indirectly with the actin cytoskeleton (27,31).…”

Section: Discussionmentioning

confidence: 99%

EhLimA, a Novel LIM Protein, Localizes to the Plasma Membrane inEntamoeba histolytica

2007

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The parasitic protozoan Entamoeba histolytica relies on a very dynamic cytoskeleton in order to invade and survive in host tissues. Identification of cytoskeletal elements is key to understanding these processes. Here we present the characterization of EhLimA, the first LIM protein of E. histolytica. EhLimA consists of a single LIM domain at its N terminus and exhibits the highest degree of homology with DdLimE from Dictyostelium discoideum. Immunofluorescence localization of EhLimA using anti-EhLimA antibodies revealed that EhLimA is highly concentrated at the plasma membrane of cells. Silencing or overexpression of the EhLimA gene did not have a significant effect on the growth or morphology of the parasite. EhLimA associates with the cytoskeleton as demonstrated by the enrichment of the protein in cytoskeleton fractions as well as in pull-down assays that revealed that cytoskeleton association involves interaction with actin. EhLimA binding to actin was shown to be dependent on the N-terminal LIM domain of EhLimA, as removal of even half of the LIM domain resulted in almost complete inhibition of the binding to actin. We also found that a portion of EhLimA floats to the lower-density regions of a sucrose gradient together with portions of the Gal-lectin light subunit and actin. Treatment of cells with the cholesterol-sequestering agent digitonin resulted in increased solubility of EhLimA. These results indicate that in addition to cytoskeletal association, EhLimA may also associate with lipid rafts in the parasite plasma membrane and suggest that EhLimA may be part of the molecular system connecting the actin cytoskeleton to membrane rafts.Many cellular functions are dependent on specific proteinprotein interactions. These protein-protein interactions are governed by a variety of protein binding domains one of which is the LIM domain. Since first described nearly 2 decades ago (21, 28, 57), LIM domain-containing proteins have been identified in a wide range of eukaryotes, including protozoa (16,30,45), plants (5,20,40), and yeast (Saccharomyces cerevisiae) (39), stressing the evolutionary importance of these proteins. In the parasitic protozoan Entamoeba histolytica, a few studies have revealed the presence of such proteins (17, 36), although to date, no LIM domain-containing proteins have been characterized in this organism. The name LIM is derived from the three developmentally regulated transcription factors, LIN-11 of Caenorhabditis elegans (21), Isl1 of rat (28), and MEC-3 of C. elegans (57) in which the LIM domain was initially identified. The LIM domain is a cysteine-rich motif consisting of two zinc finger-like modules and displaying the consensus sequence CX 2 CX 16-23 HX 2 CX 2 CX 2 CX 16-21 CX 2 (C/H/D/) (31). This domain is found in a variety of different proteins with diverse functions, including transcription factors and cytoskeleton-associated proteins, and may be found in association with other functional domains, such as homeodomains, protein kinase domains, or other protein binding domains (...

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Section: Discussionmentioning

confidence: 99%

EhLimA, a Novel LIM Protein, Localizes to the Plasma Membrane inEntamoeba histolytica

2007

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“…Amoeboid motility is also complex, although poorly understood, and requires membrane detachment from cytoskeletal components (blebbing) and rapid subsequent restructuring of actin (53). In addition to motility, E. histolytica is dependent on a dynamic actin cytoskeleton for multiple pathogenic processes such as attachment, destruction, and phagocytosis of host cells, chemotaxis, and shedding of host antibodies from the cell membrane (4,54). To begin to understand the E. histolytica Rho family GTPases role in regulating these processes via nucleotide cycling, we have now provided structural snapshots of a representative family member, EhRho1, yielding insights to its mechanisms of nucleotide-dependent activation and effector engagement.…”

Section: Discussionmentioning

confidence: 99%

Unique Structural and Nucleotide Exchange Features of the Rho1 GTPase of Entamoeba histolytica

Bosch

Wittchen

Connie

et al. 2011

Journal of Biological Chemistry

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Background: Rho family GTPases regulate Entamoeba histolytica pathogenesis. Results: Despite Ras-like structural features and fast intrinsic nucleotide exchange, EhRho1 engages classical Rho effectors and regulates actin. Conclusion: EhRho1 is a true Rho family GTPase with a unique mode of nucleotide interaction. Significance: Possibly representing an early Rho subfamily divergence from the Ras superfamily, EhRho1 likely regulates actin polymerization in E. histolytica.

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“…The particularly high rate of membrane flux seen in this organism (the membrane is turned over every 30 min) suggests highly dynamic cytoskeleton and vesicular transport systems [26]. These systems also mediate exocytosis, a process by which amebic cells can secrete hydrolytic enzymes, such as collagenase and CPs [27].…”

Section: Pathogenesis: Role Of Signaling Pathwaysmentioning

confidence: 99%

Protein Kinases of the Parasitic ProtistEntamoeba histolytica

Somlata

Babuta

Bhattacharya

et al. 2013

Protein Phosphorylation in Parasites

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The Cytoskeleton of Entamoeba histolytica: Structure, Function, and Regulation by Signaling Pathways

Cited by 59 publications

References 75 publications

EhLimA, a Novel LIM Protein, Localizes to the Plasma Membrane inEntamoeba histolytica

EhLimA, a Novel LIM Protein, Localizes to the Plasma Membrane inEntamoeba histolytica

Unique Structural and Nucleotide Exchange Features of the Rho1 GTPase of Entamoeba histolytica

Protein Kinases of the Parasitic ProtistEntamoeba histolytica

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