Das K, Watanabe N, Nozaki T. Two StAR-related lipid transfer proteins play specific roles in endocytosis, exocytosis, and motility in the parasitic protist Entamoeba histolytica.
PLoS Pathog 2021;
17:e1009551. [PMID:
33909710 PMCID:
PMC8109825 DOI:
10.1371/journal.ppat.1009551]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/10/2021] [Accepted: 04/09/2021] [Indexed: 12/26/2022] Open
Abstract
Lipid transfer proteins (LTPs) are the key contributor of organelle-specific lipid distribution and cellular lipid homeostasis. Here, we report a novel implication of LTPs in phagocytosis, trogocytosis, pinocytosis, biosynthetic secretion, recycling of pinosomes, and motility of the parasitic protist E. histolytica, the etiological agent of human amoebiasis. We show that two StAR-related lipid transfer (START) domain-containing LTPs (named as EhLTP1 and 3) are involved in these biological pathways in an LTP-specific manner. Our findings provide novel implications of LTPs, which are relevant to the elucidation of pathophysiology of the diseases caused by parasitic protists.
We showed that EhLTP1, but not EhLTP3, is involved in secretion of cysteine protease, the well-established degrading factor of host cells and the extracellular matrix, and in pseudopod formation and migration. In contrast, EhLTP3, but not EhLTP1, is exclusively involved in pinocytosis of the fluid-phase marker. Both EhLTP1 and EhLTP3 are also involved in trogocytosis (ingestion by nibbling) of live mammalian cells and phagocytosis of dead cells. In trogocytosis and phagcytosis, these two LTPs displayed distinct patterns of recruitment: e.g., EhLTP1 was associated at the ligand attachment site at the initiation of trogocytosis, followed by the recruitment of EhLTP3 onto the “trogocytic tunnel” at the intermediate stage of trogocytosis before the closure of the trogosome. Such tempo-spatially coordinated involvement of LTPs in the course of trogo- and phagocytosis has never been demonstrated in unicellular eukaryotes. Neither has LTP been shown to be involved in both endocytosis and exocytosis.
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