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Updated: Jun 22, 2026

Imaging ATG9A, a Multi-Spanning Membrane Protein
Published on: June 16, 2023
Autophagy protein 8 mediating autophagosome in encysting Acanthamoeba
Eun-Kyung Moon1, Dong-Il Chung, Yeon-Chul Hong
1Department of Parasitology, Kyungpook National University School of Medicine, 101 Dongin-dong, Joong-gu, Taegu, Republic of Korea.
Abstract:
Autophagy is an evolutionally conserved protein degradation pathway in eukaryotes. It plays essential roles during starvation, cellular differentiation, cell death, and aging by eliminating unwanted or unnecessary organelles and recycling the components for reuse. ATG8, a member of a novel ubiquitin-like protein family, is an essential component of the autophagic machinery. The present study identified and characterized autophagy protein 8 in Acanthamoeba castellanii an amphizoic amoeba causing granulomatous amoebic encephalitis and amoebic keratitis in humans. Real-time polymerase chain reaction demonstrated that the A. castellanii Atg8 (AcAtg8) gene encoding a 118 amino acid protein was highly expressed during encystation. Fluorescence microscopic analysis following transient transfection of enhanced green fluorescent protein-AcAtg8 revealed small or large vacuolar fluorescent structures in an encysting amoeba. The Atg8 fluorescent structures on the membrane were identified as autophagosomes by co-localization analysis with LysoTracker. Chemically synthesized small interfering RNA against AcAtg8 reduced the encystation efficiency and inhibited autophagosome formation in Acanthamoeba.
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