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Actin, RhoA, and Rab11 participation during encystment in Entamoeba invadens.

Herrera-Martínez M, Hernández-Ramírez VI, Lagunes-Guillén AE, Chávez-Munguía B, Talamás-Rohana P - Biomed Res Int (2013)

Bottom Line: Results showed a high level of polymerized actin accompanied by increased levels of RhoA-GTP during cell rounding and loss of vacuoles.Cytochalasin D, an actin polymerization inhibitor, and Y27632, an inhibitor of RhoA activity, reduced encystment in 80%.These results suggest that actin cytoskeleton rearrangement is playing a decisive role in determining cell morphology changes and helping with the transport of cell wall components to the cell surface during encystment of E. invadens.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 México City, DF, Mexico.

ABSTRACT
In the genus Entamoeba, actin reorganization is necessary for cyst differentiation; however, its role is still unknown. The aim of this work was to investigate the role of actin and encystation-related proteins during Entamoeba invadens encystation. Studied proteins were actin, RhoA, a small GTPase involved through its effectors in the rearrangement of the actin cytoskeleton; Rab11, a protein involved in the transport of encystation vesicles; and enolase, as an encystment vesicles marker. Results showed a high level of polymerized actin accompanied by increased levels of RhoA-GTP during cell rounding and loss of vacuoles. Cytochalasin D, an actin polymerization inhibitor, and Y27632, an inhibitor of RhoA activity, reduced encystment in 80%. These inhibitors also blocked cell rounding, disposal of vacuoles, and the proper formation of the cysts wall. At later times, F-actin and Rab11 colocalized with enolase, suggesting that Rab11 could participate in the transport of the cyst wall components through the F-actin cytoskeleton. These results suggest that actin cytoskeleton rearrangement is playing a decisive role in determining cell morphology changes and helping with the transport of cell wall components to the cell surface during encystment of E. invadens.

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Related in: MedlinePlus

Increase in RhoA-GTP levels at early times of encystment. RhoA-GTP increased at early times but decreased later on during encystment. RhoA-GTP levels were determined by G-LISA RhoA activation assay kit (Kit no. BK121, Cytoskeleton, Inc., Denver, CO). Results are the average of three independent experiments done in duplicate (*P < 0.05).
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fig6: Increase in RhoA-GTP levels at early times of encystment. RhoA-GTP increased at early times but decreased later on during encystment. RhoA-GTP levels were determined by G-LISA RhoA activation assay kit (Kit no. BK121, Cytoskeleton, Inc., Denver, CO). Results are the average of three independent experiments done in duplicate (*P < 0.05).

Mentions: G-LISA RhoA activation assays showed that, in trophozoites, RhoA-GTP levels were 2.35 ± 0.64 ρg, with a significant increase at 12 h to 5.75 ± 1.54 ρg; at 24 and 48 h RhoA-GTP levels were slightly below levels found in trophozoites (1.63 ± 0.20 and 1.30 ± 0.35 ρg, resp.), but at 72 h (1.04 ± 0.22 ρg) and 96 h (1.07 ± 0.19 ρg) these levels decreased further (Figure 6). The activation of RhoA may indicate the need of the amoeba to regulate the actin cytoskeleton rearrangement during encystment, especially at early times of the process.


Actin, RhoA, and Rab11 participation during encystment in Entamoeba invadens.

Herrera-Martínez M, Hernández-Ramírez VI, Lagunes-Guillén AE, Chávez-Munguía B, Talamás-Rohana P - Biomed Res Int (2013)

Increase in RhoA-GTP levels at early times of encystment. RhoA-GTP increased at early times but decreased later on during encystment. RhoA-GTP levels were determined by G-LISA RhoA activation assay kit (Kit no. BK121, Cytoskeleton, Inc., Denver, CO). Results are the average of three independent experiments done in duplicate (*P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3794519&req=5

fig6: Increase in RhoA-GTP levels at early times of encystment. RhoA-GTP increased at early times but decreased later on during encystment. RhoA-GTP levels were determined by G-LISA RhoA activation assay kit (Kit no. BK121, Cytoskeleton, Inc., Denver, CO). Results are the average of three independent experiments done in duplicate (*P < 0.05).
Mentions: G-LISA RhoA activation assays showed that, in trophozoites, RhoA-GTP levels were 2.35 ± 0.64 ρg, with a significant increase at 12 h to 5.75 ± 1.54 ρg; at 24 and 48 h RhoA-GTP levels were slightly below levels found in trophozoites (1.63 ± 0.20 and 1.30 ± 0.35 ρg, resp.), but at 72 h (1.04 ± 0.22 ρg) and 96 h (1.07 ± 0.19 ρg) these levels decreased further (Figure 6). The activation of RhoA may indicate the need of the amoeba to regulate the actin cytoskeleton rearrangement during encystment, especially at early times of the process.

Bottom Line: Results showed a high level of polymerized actin accompanied by increased levels of RhoA-GTP during cell rounding and loss of vacuoles.Cytochalasin D, an actin polymerization inhibitor, and Y27632, an inhibitor of RhoA activity, reduced encystment in 80%.These results suggest that actin cytoskeleton rearrangement is playing a decisive role in determining cell morphology changes and helping with the transport of cell wall components to the cell surface during encystment of E. invadens.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 México City, DF, Mexico.

ABSTRACT
In the genus Entamoeba, actin reorganization is necessary for cyst differentiation; however, its role is still unknown. The aim of this work was to investigate the role of actin and encystation-related proteins during Entamoeba invadens encystation. Studied proteins were actin, RhoA, a small GTPase involved through its effectors in the rearrangement of the actin cytoskeleton; Rab11, a protein involved in the transport of encystation vesicles; and enolase, as an encystment vesicles marker. Results showed a high level of polymerized actin accompanied by increased levels of RhoA-GTP during cell rounding and loss of vacuoles. Cytochalasin D, an actin polymerization inhibitor, and Y27632, an inhibitor of RhoA activity, reduced encystment in 80%. These inhibitors also blocked cell rounding, disposal of vacuoles, and the proper formation of the cysts wall. At later times, F-actin and Rab11 colocalized with enolase, suggesting that Rab11 could participate in the transport of the cyst wall components through the F-actin cytoskeleton. These results suggest that actin cytoskeleton rearrangement is playing a decisive role in determining cell morphology changes and helping with the transport of cell wall components to the cell surface during encystment of E. invadens.

Show MeSH
Related in: MedlinePlus