EhSir2c, a Sir2 homolog from the human pathogen Entamoeba histolytica interacts with a DNA repair protein, EhRAD23: Protein-protein interaction, docking and functional study

Abstract

Chromosome segregation is a crucial phenomenon in the cell cycle and defects in genome segregation result in an abnormality in various cellular events. Unlike higher eukaryotes, chromosome segregation and a number of cell cycle events are unusual in the protozoan parasite Entamoeba histolytica (E. histolytica). Characterization of Sir2 proteins from E. histolytica may reveal its unique cellular events as they play role in diverse cellular processes including chromosome segregation. E. histolytica has four homologs of Sir2 proteins. EhSir2a and EhSir2b show sequence similarity towards eukaryotic Sir2 homologs, whereas EhSir2c and EhSir2d are more like prokaryotic sirtuins. Using both computational and experimental methods, EhSir2c has been characterized in this study. The three-dimensional structure of EhSir2c is predicted by homology modelling. The protein interactors of EhSir2c have been identified by yeast-two-hybrid screening against the cDNA library of E. histolytica. We have identified a novel interactor, EhRAD23 which is a homolog of UV excision repair protein RAD23. The interaction of EhSir2c and EhRAD23 was validated by pull-down assay. UV-C irradiation up-regulates the relative expression of EhSir2c, suggesting the necessity of EhSir2c in UV-induced stress in this parasite.

Communicated by Ramaswamy H. Sarma

Keywords:

• Entamoeba histolytica
• Sir2
• homology modelling
• molecular docking
• yeast-two-hybrid library screening
• protein-protein interaction

Disclosure statement

The authors declare that they have no conflict of interest.

Authors’ contributions

PB and SD designed the study. PB performed most of the experiments. RG and SP assisted in DNA cloning. MD was involved in UV experiment. PB and SD wrote and edited the manuscript. All authors read and approved the final manuscript.

Additional information

Funding

This study was partially funded by DAE-BRNS, Govt. of India (Project No. 37 (1)/20/15/2014-BRNS; 2014-2017) and CSIR, Govt. of India (Project No. 27(0322)/17/EMR-II; 2017–2020) to SD and PB was supported by State-funded fellowship, The University of Burdwan, West Bengal, India. We thank Dr. Bomba Dam, Department of Botany, Visva-Bharati, Santiniketan for his kind help to perform Real-Time PCR.