γ-Carboxymuconolactone decarboxylase: a novel cell cycle-related basal body protein in the early branching eukaryote Trichomonas vaginalis

Abstract

Backgroundγ-Carboxymuconolactone decarboxylase (CMD) participates in the β-ketoadipate pathway, which catalyzes aromatic compounds to produce acetyl- or succinyl-CoA, in prokaryotes and yeast. Our previous study demonstrated that expression of a CMD homologue that contains two signatures (dualCMD) is negatively regulated by iron in Trichomonas vaginalis. However, we were not able to identify the components of the β-ketoadipate pathway in the parasite’s genome. These observations prompted us to investigate the biological functions of this novel CMD homologue in T. vaginalis.MethodsThe specific anti-TvCMD1 antibody was generated, and the expression of TvCMD1 in T. vaginalis cultured under iron-rich and iron-deficient were evaluated. Phylogenetic, metabolomic and substrate induction (protocatechuate and benzoate) analysis were conducted to clarify the function of dualCMD in trichomonad cells. Subcellular localization of TvCMD1 was observed by confocal microscopy. The cell cycle-related role of TvCMD1 was assessed by treating cells with G2/M inhibitor nocodazole.ResultsWe confirmed that T. vaginalis is not able to catabolize the aromatic compounds benzoate and protocatechuate, which are known substrates of the β-ketoadipate pathway. Using immunofluorescence microscopy, we found that TvCMD1 is spatially associated with the basal body, a part of the cytoskeletal organizing center in T. vaginalis. TvCMD1 accumulated upon treatment with the G2/M inhibitor nocodazole. Additionally, TvCMD1 was expressed and transported to/from the basal body during cytokinesis, suggesting that TvCMD1 plays a role in cell division.ConclusionWe demonstrated that TvCMD1 is unlikely to participate in the β-ketoadipate pathway and demonstrated that it is a novel basal body-localizing (associated) protein. This model sheds light on the importance of genes that are acquired laterally in the coevolution of ancient protists, which surprisingly functions in cell cycle regulation of T. vaginalis.Electronic supplementary materialThe online version of this article (10.1186/s13071-017-2381-4) contains supplementary material, which is available to authorized users.

In-Depth Quantitative Proteomic Analysis of Trophozoites and Pseudocysts of Trichomonas vaginalis

“…In fact, the trophozoite population exhibited an average of 67.3% ± 5% cells in the G1 phase, 23.3% ± 5.3% cells in the S phase, and 9.3% ± 1.8% cells in the G2/M phase (Figure C), whereas pseudocysts exhibited an average of 48.8% ± 3.6% cells in the G1 phase, 25% ± 0.9% cells in the S phase, and 26.1% ± 3.4% cells in the G2/M phase (Figure C). Thus, our results agree with those previously reported that show a positive correlation between the G2/M phase and CMD1 abundance in T. vaginalis cultivated in conditions of iron depletion . Since CDM1 has been located in the basal body of the parasites, and its mRNA and protein abundance are modulated during cell cycle, this protein has been associated with the regulation of cell cycle progression, particularly cytokinesis .…”

“…In addition, we observed in pseudocysts a significant 50-fold increase in the abundance of 4-carboxy­muconolactone decarboxylase family protein 1 (CMD1) (Figure A). It has been shown that CMD1 expression is induced by different stress conditions, such as iron depletion, cold treatment, and glucose restriction. ,, It has also been recently observed that parasites cultivated under conditions of iron depletion exhibited a substantial increase in CMD1 expression concomitant with a reduction of cells in the G1/S phase and an increase in the number of cells in the G2/M phase . Thus, we assessed the cell cycle of trophozoites and pseudocysts to determine the proportion of cells in each stage.…”

“…40,41,50 It has also been recently observed that parasites cultivated under conditions of iron depletion exhibited a substantial increase in CMD1 expression concomitant with a reduction of cells in the G1/S phase and an increase in the number of cells in the G2/M phase. 88 Thus, we assessed the cell cycle of trophozoites and pseudocysts to determine the proportion of cells in each stage. The histograms constructed using the ModFit LT 5.0 software revealed that the pseudocyst population exhibits a significant reduction in the percentage of G1 cells and a significant increase in the percentage of G2/M cells (Figure 9B).…”

Genomic and Phenotypic Biology of Novel Strains of Dickeya zeae Isolated From Pineapple and Taro in Hawaii: Insights Into Genome Plasticity, Pathogenicity, and Virulence Determinants

“…The genomes of two novel strains were analyzed extensively. The genome A5410 harbored some important unique genes, such as transporter proteins, endonuclease protein, phage tail protein, aspartate/glutamate racemase family protein arsD gene involved in arsenic resistance ( Firrincieli et al, 2019 ), and the carboxymuconolactone decarboxylase protein involved in protocatechuate catabolism ( Cheng et al, 2017 ). The nitrogen fixation gene cluster was only present in the A5410 strain isolated from pineapple ( Figure 7A ).…”

“…The nitrogen fixation cluster was also present in D. solani and P. atrosepticum ( Bell et al, 2004 ; Golanowska, 2015 ). Carboxymuconolactone decarboxylase participates in the catalysis of aromatic compounds to produce acetyl- or succinyl-CoA in prokaryotes and yeast ( Cheng et al, 2017 ). Carboxymuconolactone decarboxylase was present in Azotobacter vinelandii, Acinetobacter calcoaceticus , and Pseudomonas putida ( Yeh et al, 1981 ).…”