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Updated: Jul 10, 2026
Two-Step Tag-Free Isolation of Mitochondria for Improved Protein Discovery and Quantification
Published on: June 2, 2023
A mitosome purification protocol based on percoll density gradients and its use in validating the mitosomal nature of
Jorge Tovar1, Siân S E Cox, Mark van der Giezen
1School of Biological Sciences, Royal Holloway, University of London, Egham, United Kingdom.
Abstract:
Mitochondria are indispensable for aerobic respiration, but many microbial eukaryotes have lost this function through reductive evolution. Their modified mitochondria are known as hydrogenosomes or mitosomes depending on whether or not they produce molecular hydrogen. The intestinal parasite Entamoeba histolytica contains mitosomes whose role in cellular metabolism is unclear. Only three proteins have been shown thus far to reside in these organelles: the molecular chaperones Hsp10 and Hsp60 and an unusual ADP/ATP carrier. Here we describe the isolation of E. histolytica mitosomes by cellular fractionation and density gradient centrifugation and show that the mitochondrial-type chaperone Hsp70 is also housed in Entamoeba mitosomes.
Insights
Mitochondria are vital for respiration, but some microbes lose this function. This study identifies a new protein, Hsp70, within the mitosomes of the parasite Entamoeba histolytica, shedding light on their metabolic roles.
Area of Science:
- Microbiology
- Cell Biology
- Parasitology
Background:
- Mitochondria are essential for aerobic respiration in most eukaryotes.
- Some microbial eukaryotes undergo reductive evolution, modifying or losing mitochondrial function.
- Modified mitochondria include hydrogenosomes and mitosomes, with the latter found in Entamoeba histolytica and having an unclear metabolic role.
Purpose of the Study:
- To investigate the protein composition and function of Entamoeba histolytica mitosomes.
- To identify novel proteins localized within these organelles.
Main Methods:
- Isolation of Entamoeba histolytica mitosomes using cellular fractionation.
- Purification of mitosomes via density gradient centrifugation.
- Analysis of protein content within isolated mitosomes.
Main Results:
- Successful isolation and purification of Entamoeba histolytica mitosomes.
- Identification of the mitochondrial-type chaperone Hsp70 within these mitosomes.
- This finding expands the known proteome of Entamoeba histolytica mitosomes beyond previously identified proteins (Hsp10, Hsp60, ADP/ATP carrier).
Conclusions:
- The mitochondrial chaperone Hsp70 is localized to Entamoeba histolytica mitosomes.
- This discovery contributes to understanding the metabolic functions of these highly reduced organelles.
- Further research is warranted to elucidate the specific roles of Hsp70 in mitosome function.
