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bioRxiv · 10.1101/2025.10.24.684426

Pleckstrin homology domain-containing serine/threonine kinase plays a crucial role in the survival and phagocytosis of Entamoeba histolytica.

Mishra, S.·Tomar, P.·Bhattacharya, A.·Gourinath, S.
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Abstract

Kinases are critical regulators of parasite survival, cytoskeletal dynamics, and endocytic processes. Entamoeba histolytica encodes 372 kinases, many of which remain functionally uncharacterized. This study characterizes EhPHDK, an AGC-family kinase essential for pseudopod formation, phagocytosis, and pinocytosis. Structural modelling suggests an autoregulatory mechanism via its PH domain, potentially modulating kinase activity. Bio-layer interferometry identified a crucial amino acid sequence facilitating interaction with EhCaBP1, implicating EhPHDK in endocytic regulation. Live-cell imaging and immunostaining confirmed its dynamic recruitment to the plasma membrane, colocalizing with EhCaBP1 during phagocytosis initiation and progression. Gene silencing severely impaired parasite viability, reducing growth by 90%, while RBC uptake assays demonstrated its indispensable role in phagocytosis. The regulatory interplay between EhPHDK and cytoskeletal components underscores its function in actin-driven processes. Given its divergence from host kinases, EhPHDK presents a promising therapeutic target for amebiasis. This study provides novel insights into kinase-mediated cytoskeletal remodelling, advancing our understanding of E. histolytica pathogenesis and offering potential avenues for intervention in parasitic survival mechanisms. HighlightsO_LIEhPHDK kinase regulates pseudopod formation, phagocytosis, and pinocytosis. C_LIO_LIStructural modelling suggests PH domain autoregulation of kinase activity. C_LIO_LIEhPHDK interacts with EhCaBP1, influencing endocytosis and cytoskeletal dynamics. C_LIO_LIGene silencing reduces parasite survival by 90%, impairing phagocytosis. C_LIO_LIEhPHDK is a potential therapeutic target, diverging from host kinases. C_LI

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Mishra, S., Tomar, P., Bhattacharya, A., Gourinath, S.. 2025-10-26. Pleckstrin homology domain-containing serine/threonine kinase plays a crucial role in the survival and phagocytosis of Entamoeba histolytica.. https://doi.org/10.1101/2025.10.24.684426

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