Calcium binding protein 1 of the protozoan parasite<i>Entamoeba histolytica</i>interacts with actin and is involved in cytoskeleton dynamics

Sahoo, Nivedita; Labruyère, Elisabeth; Bhattacharya, Sudha; Sen, Pratik; Guillén, Nancy; Bhattacharya, Alok

doi:10.1242/jcs.01198

Cited by 91 publications

(160 citation statements)

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“…Though there may be significant differences in the mechanisms of phagosome initiation in different organisms, and a variety of molecules may be involved in the process, it is likely that a similar theme may be operational in other systems. Moreover, phagocytosis is an essential process in many organisms including E. histolytica in which cellular proliferation is inhibited on blocking phagocytosis 30 . Unravelling the mechanism of phagocytosis may be helpful in finding novel targets for the development of new therapeutics.…”

Section: Discussionmentioning

confidence: 99%

“…E. histolytica strain HM-1: IMSS and all transformed parasites were maintained and grown in TYI-S-33 medium containing 125 µl of 250 U ml − 1 benzyl penicillin and 0.25 mg ml − 1 streptomycin per 100 ml of medium 30 . The transformants containing tetracycline inducible system were grown in the presence of 10 µg ml − 1 of hygromycin B.…”

Section: Methodsmentioning

confidence: 99%

“…4a) using tetracycline inducible antisense expression, as previously described 30 . Overexpression of antisense EhC2PK RNA in the presence of tetracycline specifically reduced the level of EhC2PK by about 70% without affecting the levels of EhCaBP1 (Fig.…”

Section: Ehc2pk Is Involved In Erythrophagocytosismentioning

confidence: 99%

“…Our previous studies have shown the involvement of E. histolytica calcium-binding protein (EhCaBP1) in actin dynamics. Downregulation of this protein leads to defects in both phagocytosis and pseudopod formation 30 . EhCaBP1 binds both G-and F-actin in vitro and in vivo.…”

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confidence: 99%

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A C2 domain protein kinase initiates phagocytosis in the protozoan parasite Entamoeba histolytica

Somlata

Bhattacharya

2011

Nat Commun

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Phagocytosis is a process whereby particles are taken in by cells through mechanisms super ficially similar to those for endocytosis. It serves a wide range of functions, from providing nutrition in unicellular organisms to initiation of both innate and adaptive immunity in vertebrates. In the protozoan parasite Entamoeba histolytica, it has an essential role in survival and pathogenesis. In this study, we show that EhC2PK, a C2 domain containing protein kinase, and the Ca 2 + and actin binding protein, EhCaBP1, are involved in the initiation of phagocytosis in E. histolytica. Conditional suppression of EhC2PK expression and overexpression of a mutant form reveals its role in the initiation of phagocytic cups. EhC2PK binds phosphatidylserine in the presence of Ca 2 + and thereby recruits EhCaBP1 and actin to the membrane. Identification of these proteins in phagocytosis is an important step in amoebic biology and these molecules could be the important targets for developing novel therapies against amoebiasis.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Ehc2pk Is Involved In Erythrophagocytosismentioning

confidence: 99%

mentioning

confidence: 99%

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A C2 domain protein kinase initiates phagocytosis in the protozoan parasite Entamoeba histolytica

Somlata

Bhattacharya

2011

Nat Commun

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“…Intracellular calcium plays an important role in differentiation [19], motility [8,20], cytoskeletal dynamics [21] and cell growth [22,23] in protozoan parasites. In addition to the normal intracellular calcium storage pools in the ER and mitochondria, protozoa also contain a unique intracellular organelle for calcium storage called the acidocalcisome [24,25].…”

Section: Introductionmentioning

confidence: 99%

Evidence that the cADPR signalling pathway controls calcium-mediated microneme secretion in Toxoplasma gondii

Chini

Nagamune

Wetzel

et al. 2005

Biochemical Journal

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The protozoan parasite Toxoplasma gondii relies on calciummediated exocytosis to secrete adhesins on to its surface where they can engage host cell receptors. Increases in intracellular calcium occur in response to Ins(1,4,5)P 3 and caffeine, an agonist of ryanodine-responsive calcium-release channels. We examined lysates and microsomes of T. gondii and detected evidence of cADPR (cyclic ADP ribose) cyclase and hydrolase activities, the two enzymes that control the second messenger cADPR, which causes calcium release from RyR (ryanodine receptor). We also detected endogenous levels of cADPR in extracts of T. gondii. Furthermore, T. gondii microsomes that were loaded with 45 Ca 2+ released calcium when treated with cADPR, and the RyR antagonists 8-bromo-cADPR and Ruthenium Red blocked this response. Although T. gondii microsomes also responded to Ins(1,4,5)P 3 , the inhibition profiles of these calcium-release channels were mutually exclusive. The RyR antagonists 8-bromocADPR and dantrolene inhibited protein secretion and motility in live parasites. These results indicate that RyR calcium-release channels that respond to the second-messenger cADPR play an important role in regulating intracellular Ca 2+ , and hence host cell invasion, in protozoan parasites.

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Crystal structure of calcium binding protein‐1 from Entamoeba histolytica: A novel arrangement of EF hand motifs

et al. 2007

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Calcium plays a pivotal role in the pathogenesis of amoebiasis, a major disease caused by Entamoeba histolytica. Several EF-hand containing calcium-binding proteins (CaBPs) have been identified from E. histolytica. Even though these proteins have very high sequence similarity, they bind to different target proteins in a Ca2+ dependent manner, leading to different functional pathways (Yadava et al., Mol Biochem Parasito 1997;84:69-82; Chakrabarty et al., J Biol Chem 2004;279:12898-12908) The crystal structure of the Entamoeba histolytica calcium binding protein-1 (EhCaBP1) has been determined at 2.4 A resolution. The crystals were grown using MPD as precipitant and they belong to P6(3) space group with unit cell parameters of a = 95.25 A, b = 95.25 A, c = 64.99 A. Only two out of the four expected EF hand motifs could be modeled into the electron density map and the final model refined to R factor of 25.6% and Free_R of 28%. Unlike CaM, the first two EF hand motifs in EhCaBP1 are connected by a long helix and form a dumbbell shaped structure. Owing to domain swapping oligomerization three EhCaBP1 molecules interact in a head to tail manner to form a triangular trimer. This arrangement allows the EF-hand motif of one molecule to interact with that of an adjacent molecule to form a two EF-hand domain similar to that seen in the N-terminal domain of the NMR structure of CaBP1, calmodulin and troponin C. The oligomeric state of EhCaBP1 results in reduced flexibility between domains and may be responsible for the more limited set of targets recognized by EhCaBP1.

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Calcium binding protein 1 of the protozoan parasiteEntamoeba histolyticainteracts with actin and is involved in cytoskeleton dynamics

Cited by 91 publications

References 36 publications

A C2 domain protein kinase initiates phagocytosis in the protozoan parasite Entamoeba histolytica

A C2 domain protein kinase initiates phagocytosis in the protozoan parasite Entamoeba histolytica

Evidence that the cADPR signalling pathway controls calcium-mediated microneme secretion in Toxoplasma gondii

Crystal structure of calcium binding protein‐1 from Entamoeba histolytica: A novel arrangement of EF hand motifs

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