Ca2+-binding protein from Entamoeba histolytica (EhCaBP6) is a novel GTPase

A Review: Natural and Synthetic Compounds Targeting Entamoeba histolytica and Its Biological Membrane

Amoebiasis is the third most common parasitic cause of morbidity and mortality, particularly in countries with poor hygienic settings in central and south America, Africa, and India. This disease is caused by a protozoan parasite, namely Entamoeba histolytica, which infects approximately 50 million people worldwide, resulting in 70,000 deaths every year. Since the 1960s, E. histolytica infection has been successfully treated with metronidazole. However, there are drawbacks to metronidazole therapy: the side effects, duration of treatment, and need for additional drugs to prevent transmission. Previous interdisciplinary studies, including biophysics, bioinformatics, chemistry, and, more recently, lipidomics studies, have increased biomembranes’ publicity. The biological membranes are comprised of a mixture of membrane and cytosolic proteins. They work hand in hand mainly at the membrane part. They act as dedicated platforms for a whole range of cellular processes, such as cell proliferation, adhesion, migration, and intracellular trafficking, thus are appealing targets for drug treatment. Therefore, this review aims to observe the updated trend of the research regarding the biological membranes of E. histolytica from 2015 to 2021, which may help further research regarding the drug targeting the biological membrane.

Structural and functional diversity of Entamoeba histolytica calcium-binding proteins

Entamoeba histolytica (E. histolytica) is an etiological agent of human amoebic colitis, and it causes a high level of morbidity and mortality worldwide, particularly in developing countries. Ca2+ plays a pivotal role in amoebic pathogenesis, and Ca2+-binding proteins (CaBPs) of E. histolytica appear to be a major determinant in this process. E. histolytica has 27-EF-hand containing CaBPs, suggesting that this organism has complex Ca2+ signaling cascade. E. histolytica CaBPs share (29-47%) sequence identity with ubiquitous Ca2+-binding protein calmodulin (CaM); however, they do not show any significant structural similarity, indicating lack of a typical CaM in this organism. Structurally, these CaBPs are very diverse among themselves, and perhaps such diversity allows them to recognize different cellular targets, thereby enabling them to perform a range of cellular functions. The presence of such varied signaling molecules helps parasites to invade host cells and advance in disease progression. In the past two decades, tremendous progress has been made in understanding the structure of E. histolytica CaBPs by using the X-ray or NMR method. To gain greater insight into the structural and functional diversity of these amoebic CaBPs, we analyzed and compiled all the available literature. Most of the CaBPs has about 150 amino acids with 4-EF hand or EF-hand-like sequences, similar to CaM. In a few cases, all the EF-hand motifs are not capable of binding Ca2+, suggesting them to be pseudo EF-hand motifs. The CaBPs perform diverse cellular signaling that includes cytoskeleton remodeling, phagocytosis, cell proliferation, migration of trophozoites, and GTPase activity. Overall, the structural and functional diversity of E. histolytica CaBPs compiled here may offer a basis to develop an efficient drug to counter its pathogenesis.