Acanthamoeba castellanii: Gene profile of encystation by ESTs analysis and KOG assignment

Moon, Eun‐Kyung; Chung, Dong‐Il; Hong, Yeonchul; Ahn, Tae In; Kong, Hyun-Hee

doi:10.1016/j.exppara.2008.01.001

Cited by 36 publications

(40 citation statements)

References 20 publications

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“…It is likely that these enzymes might be related to cellulose synthesis (4). The induction of enolase in cysts confirmed a previous study conducted at the mRNA level in Acanthamoeba (39). Finally, enolase is also involved in differentiation of Entamoeba histolytica and was localized at the cyst wall, suggesting a role different from the one in the glycolytic pathway (55,56).…”

Section: Cell Wall Synthesissupporting

confidence: 69%

“…Despite the fact that the precise cellular localization is not known, immunodetection results suggest that this protein is associated with cyst walls (24). Studies at the mRNA level have confirmed its early expression during the encystment process (10) and that this expression is specific for cysts (39). However, the role of this protein is not established yet.…”

Section: The Cyst-specific Protein Csp21mentioning

confidence: 88%

“…One of them, a subtilisin-like serine protease, is clearly associated to encystment. The mRNA corresponding to this protein is induced during encystment (39,40). The protein is also specifically detected in cysts, as shown by twodimensional (2D) gel electrophoresis (4,47).…”

Section: Proteasesmentioning

confidence: 96%

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Cellular, Biochemical, and Molecular Changes during Encystment of Free-Living Amoebae

Fouque

Trouilhé

Thomas³

et al. 2012

Eukaryot Cell

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ABSTRACTFree-living amoebae are protozoa found in soil and water. Among them, some are pathogenic and many have been described as potential reservoirs of pathogenic bacteria. Their cell cycle is divided into at least two forms, the trophozoite and the cyst, and the differentiation process is named encystment. As cysts are more resistant to disinfection treatments than trophozoites, many studies focused on encystment, but until recently, little was known about cellular, biochemical, and molecular modifications operating during this process. Important signals and signaling pathways at play during encystment, as well as cell responses at the molecular level, have been described. This review summarizes our knowledge and focuses on new findings.

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Section: Cell Wall Synthesissupporting

confidence: 69%

Section: The Cyst-specific Protein Csp21mentioning

confidence: 88%

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Cellular, Biochemical, and Molecular Changes during Encystment of Free-Living Amoebae

Fouque

Trouilhé

Thomas³

et al. 2012

Eukaryot Cell

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“…To identify the serine proteinase associated with encystation of Acanthamoeba, we screened expressed sequence tag (EST) data of encysted Acanthamoeba (20). Five kinds of proteinases were identified in cyst cDNA library ESTs.…”

Section: Proteolytic Activity During Acanthamoeba Encystationmentioning

confidence: 99%

Characterization of a Serine Proteinase Mediating Encystation of Acanthamoeba

et al. 2008

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Members of the genus Acanthamoeba, amphizoic protozoan parasites, are causative agents of granulomatous amoebic encephalitis and amoebic keratitis. Proteinases play a role in various biologic actions in Acanthamoeba, including host tissue destruction, pathogenesis, and digestion of phagocytosed food. Interestingly, we found that encystation of Acanthamoeba was inhibited by the serine proteinase inhibitor phenylmethanesulfonyl fluoride. In this study, we characterize a serine proteinase that is involved in mediating the encystation of Acanthamoeba. This encystation-mediating serine proteinase (EMSP) is shown to be highly expressed during encystation by real-time PCR and Western blot analysis. Chemically synthesized small interfering RNA against EMSP inhibited the expression of EMSP mRNA and significantly reduced the encystation efficiency of Acanthamoeba. An EMSPenhanced green fluorescent protein fusion protein localized to vesicle-like structures within the amoeba. Using LysoTracker analysis, these vesicular structures were confirmed to be lysosomes. After incubation of the transfected amoeba in encystment media, small fluorescent vesicle-like structures gathered and formed ball-like structures, which were identified as colocalizing with the autophagosome. Taken together, these results indicate that EMSP plays an important role in the differentiation of Acanthamoeba by promoting autolysis.

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“…Previous studies on Giardia and Entamoeba have shown that cysteine proteases are implicated in parasite survival under nutrient-limited conditions and during developmental differentiation (9-14). In Acanthamoeba, the cysteine protease inhibitor E64d was found to slow encystment (15), and in a previous study, we detected the upregulations of various proteases, including cysteine proteases, by cDNA microarray analysis and comparative expression analysis of expressed sequence tags (ESTs) during encystation (16,17). Cysteine proteases in lysosomes cause massive proteolytic degradation of unnecessary cytosolic compartments or organelles during encystation and thus must be strictly controlled to protect essential intracellular components from damage for subsequent excystation of cysts to viable trophozoites.…”

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confidence: 99%

Cysteine Protease Inhibitor (AcStefin) Is Required for Complete Cyst Formation of Acanthamoeba

et al. 2013

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dThe encystation of Acanthamoeba leads to the formation of resilient cysts from vegetative trophozoites. This process is essential for parasite survival under unfavorable conditions, such as those associated with starvation, low temperatures, and biocides. Furthermore, cysteine proteases have been implicated in the massive turnover of intracellular components required for encystation. Thus, strict modulation of the activities of cysteine proteases is required to protect Acanthamoeba from intracellular damage. However, mechanisms underlying the control of protease activity during encystation have not been established in Acanthamoeba. In the present study, we identified and characterized Acanthamoeba cysteine protease inhibitor (AcStefin), which was found to be highly expressed during encystation and to be associated with lysosomes by fluorescence microscopy. Recombinant AcStefin inhibited various cysteine proteases, including human cathepsin B, human cathepsin L, and papain. Transfection with small interfering RNA against AcStefin increased cysteine protease activity during encystation and resulted in incomplete cyst formation, reduced excystation efficiency, and a significant reduction in cytoplasmic area. Taken together, these results indicate that AcStefin is involved in the modulation of cysteine proteases and that it plays an essential role during the encystation of Acanthamoeba.A canthamoeba is the causative agent of granulomatous amoebic encephalitis (GAE) and amoebic keratitis. The life cycle of Acanthamoeba is divided into two stages, that is, the vegetative trophozoite stage and the dormant cystic stage. Under challenging conditions, such as those associated with starvation, low temperatures, and biocide treatment, the trophozoite converts to the resilient cyst form (1-5). This differentiation, which is termed encystation, protects Acanthamoeba against host immune responses and allows it to evade the effect of chemical treatments, and thus, encystation decreases treatment efficacies (3, 6). Therefore, the inhibition of encystation during medical treatment could lead to outcomes that are more favorable in cases of amoebic infection. However, this goal is hindered by a lack of information about the encystation mechanism involved.The cysteine proteases are regarded as major drug targets, and the papain family of cysteine proteases, such as cathepsin B and cathepsin L, are localized in lysosomes for intracellular protein degradation (7,8). Previous studies on Giardia and Entamoeba have shown that cysteine proteases are implicated in parasite survival under nutrient-limited conditions and during developmental differentiation (9-14). In Acanthamoeba, the cysteine protease inhibitor E64d was found to slow encystment (15), and in a previous study, we detected the upregulations of various proteases, including cysteine proteases, by cDNA microarray analysis and comparative expression analysis of expressed sequence tags (ESTs) during encystation (16,17). Cysteine proteases in lysosomes cause massive proteolytic de...

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Acanthamoeba castellanii: Gene profile of encystation by ESTs analysis and KOG assignment

Cited by 36 publications

References 20 publications

Cellular, Biochemical, and Molecular Changes during Encystment of Free-Living Amoebae

Cellular, Biochemical, and Molecular Changes during Encystment of Free-Living Amoebae

Characterization of a Serine Proteinase Mediating Encystation of Acanthamoeba

Cysteine Protease Inhibitor (AcStefin) Is Required for Complete Cyst Formation of Acanthamoeba

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