Protein secretion
Secretome of Trichomonas vaginalis
Secretome of Trichomonas vaginalis
The secretion of virulence factors by parasitic protists into the host environment plays a fundamental role in multifactorial host–parasite interactions. Several effector proteins had been known to be secreted by Trichomonas vaginalis, a human parasite of the urogenital tract. However, a comprehensive profiling of the T. vaginalis secretome remained elusive, as did the mechanisms of protein secretion. We used high-resolution label-free quantitative MS to analyze the T. vaginalis secretome, considering that secretion is a time- and temperature-dependent process, to define the cutoff for secreted proteins. In total, we identified 2 072 extracellular proteins, 89 of which displayed significant quantitative increases over time at 37 °C. To trace classical (Golgi-ER) pathway in T. vaginalis cells, we used beta amylases as model cargo.
The secretion of virulence factors by parasitic protists into the host environment plays a fundamental role in multifactorial host–parasite interactions. Several effector proteins had been known to be secreted by Trichomonas vaginalis, a human parasite of the urogenital tract. However, a comprehensive profiling of the T. vaginalis secretome remained elusive, as did the mechanisms of protein secretion. We used high-resolution label-free quantitative MS to analyze the T. vaginalis secretome, considering that secretion is a time- and temperature-dependent process, to define the cutoff for secreted proteins. In total, we identified 2 072 extracellular proteins, 89 of which displayed significant quantitative increases over time at 37 °C. To trace classical (Golgi-ER) pathway in T. vaginalis cells, we used beta amylases as model cargo.
Amylase in green, ER marker in red, arrows indicate Golgi
Amylase in green, ER marker in red, arrows indicate Golgi
Hydrogenosomal enzymes are not moonlighting proteins
Hydrogenosomal enzymes are not moonlighting proteins
The enzymes pyruvate ferredoxin oxidoreductase (PFO), malic enzyme (ME), and the a- and b-subunits of succinyl-CoA synthetase (SCS) catalyze key steps of energy metabolism in Trichomonas vaginalis hydrogenosomes. Other authors have also characterized these proteins as adhesins AP120 (PFO), AP65 (ME), AP33, and AP51 (a- and b-SCS) supposedly localized on the cell surface and mediating T. vaginalis cytoadherence.
The enzymes pyruvate ferredoxin oxidoreductase (PFO), malic enzyme (ME), and the a- and b-subunits of succinyl-CoA synthetase (SCS) catalyze key steps of energy metabolism in Trichomonas vaginalis hydrogenosomes. Other authors have also characterized these proteins as adhesins AP120 (PFO), AP65 (ME), AP33, and AP51 (a- and b-SCS) supposedly localized on the cell surface and mediating T. vaginalis cytoadherence.
Are these proteins really localized on the cell surface? We have excluded the possibility that these proteins would be targeted to the cellular membrane via classical secretory pathway. In contrast, we prove their very specific targeting to hydrogenosomes, which argues against their secretion and putative moonlighting function.
Are these proteins really localized on the cell surface? We have excluded the possibility that these proteins would be targeted to the cellular membrane via classical secretory pathway. In contrast, we prove their very specific targeting to hydrogenosomes, which argues against their secretion and putative moonlighting function.
Alpha-succinyl CoA synthetase (a-SCS, putative AP33) and malic enzyme (ME, putative AP65) colocalized in hydrogenosomes. a-SCS was labelled by activity of cytosolic BirA and imported exclusively to the hydrogenosomes.
Alpha-succinyl CoA synthetase (a-SCS, putative AP33) and malic enzyme (ME, putative AP65) colocalized in hydrogenosomes. a-SCS was labelled by activity of cytosolic BirA and imported exclusively to the hydrogenosomes.
Publications:
Publications:
Štáfková et al., Mol Cell Prot, 2018
Rada et al., J. Euk. Microbiol. 2019