The free-living flagellate Paratrimastix pyriformis uses a distinct mitochondrial carrier to balance adenine nucleotide pools

SLC25 family with energy metabolism and immunity in malignant tumors

Solute Carrier Family 25 (SLC25) is the largest family of mitochondrial membrane proteins in the human body, consisting of 53 members. Mitochondrial phosphate carriers (MPiC), cellular iron metabolism, voltage-dependent anion channels (VDAC), and oxidative phosphorylation in the SLC25 family play dominant roles in material transport, energy metabolism, etc. SLC25 family-related proteins are involved in the regulation of the progression of a variety of cancers, including colon, gastric, and lung cancers. In addition, the SLC25 family has been implicated in endoplasmic reticulum stress (ERS) and immunity. Since SLC25 family proteins are involved in cancer progression and are associated with endoplasmic reticulum stress and immunity, exploring inhibitors of SLC25 family-related proteins is essential. However, the exact mechanism of SLC25 family-related proteins involved in cancer, as well as potential targets and SLC25 inhibitors have not been reported in the literature. This article focuses on summarizing the relevance of the SLC25 family to cancer, ERS, and immunity. This review also provides a comprehensive overview of SLC25 family-related inhibitors.

Genomics of Preaxostyla Flagellates Illuminates the Path Towards the Loss of Mitochondria

The notion that mitochondria cannot be lost was shattered with the report of an oxymonad Monocercomonoides exilis, the first eukaryote arguably without any mitochondrion. Yet, questions remain about whether this extends beyond the single species and how this transition took place. The Oxymonadida is a group of gut endobionts taxonomically housed in the Preaxostyla which also contains free-living flagellates of the genera Trimastix and Paratrimastix. The latter two taxa harbour conspicuous mitochondrion-related organelles (MROs). Here we report high-quality genome and transcriptome assemblies of two Preaxostyla representatives, the free-living Paratrimastix pyriformis and the oxymonad Blattamonas nauphoetae. We performed thorough comparisons among all available genomic and transcriptomic data of Preaxostyla to further decipher the evolutionary changes towards amitochondriality, endobiosis, and unstacked Golgi. Our results provide insights into the metabolic and endomembrane evolution, but most strikingly the data confirm the complete loss of mitochondria for all three oxymonad species investigated (M. exilis, B. nauphoetae, and Streblomastix strix), suggesting the amitochondriate status is common to a large part if not the whole group of Oxymonadida. This observation moves this unique loss to 100 MYA when oxymonad lineage diversified.

Comparative analysis of mitochondrion-related organelles in anaerobic amoebozoans

Archamoebae comprises free-living or endobiotic amoebiform protists that inhabit anaerobic or microaerophilic environments and possess mitochondrion-related organelles (MROs) adapted to function anaerobically. We compared in silico reconstructed MRO proteomes of eight species (six genera) and found that the common ancestor of Archamoebae possessed very few typical components of the protein translocation machinery, electron transport chain and tricarboxylic acid cycle. On the other hand, it contained a sulphate activation pathway and bacterial iron-sulphur (Fe-S) assembly system of MIS-type. The metabolic capacity of the MROs, however, varies markedly within this clade. The glycine cleavage system is widely conserved among Archamoebae, except in Entamoeba, probably owing to its role in catabolic function or one-carbon metabolism. MRO-based pyruvate metabolism was dispensed within subgroups Entamoebidae and Rhizomastixidae, whereas sulphate activation could have been lost in isolated cases of Rhizomastix libera, Mastigamoeba abducta and Endolimax sp. The MIS (Fe-S) assembly system was duplicated in the common ancestor of Mastigamoebidae and Pelomyxidae, and one of the copies took over Fe-S assembly in their MRO. In Entamoebidae and Rhizomastixidae, we hypothesize that Fe-S cluster assembly in both compartments may be facilitated by dual localization of the single system. We could not find evidence for changes in metabolic functions of the MRO in response to changes in habitat; it appears that such environmental drivers do not strongly affect MRO reduction in this group of eukaryotes.