Eukaryotic proteins in the pathogenic bacterium Legionella pneumophila.

Department of ParasitologyKatedra parazitologieFaculty of SciencePřírodovědecká fakult

Evolution of mitochondrial TAT translocases illustrates the loss of bacterial protein transport machines in mitochondria

Abstract Background Bacteria and mitochondria contain translocases that function to transport proteins across or insert proteins into their inner and outer membranes. Extant mitochondria retain some bacterial-derived translocases but have lost others. While BamA and YidC were integrated into general mitochondrial protein transport pathways (as Sam50 and Oxa1), the inner membrane TAT translocase, which uniquely transports folded proteins across the membrane, was retained sporadically across the eukaryote tree. Results We have identified mitochondrial TAT machinery in diverse eukaryotic lineages and define three different types of eukaryote-encoded TatABC-derived machineries (TatAC, TatBC and TatC-only). Here, we investigate TatAC and TatC-only machineries, which have not been studied previously. We show that mitochondria-encoded TatAC of the jakobid Andalucia godoyi represent the minimal functional pathway capable of substituting for the Escherichia coli TatABC complex and can transport at least one substrate. However, selected TatC-only machineries, from multiple eukaryotic lineages, were not capable of supporting the translocation of this substrate across the bacterial membrane. Despite the multiple losses of the TatC gene from the mitochondrial genome, the gene was never transferred to the cell nucleus. Although the major constraint preventing nuclear transfer of mitochondrial TatC is likely its high hydrophobicity, we show that in chloroplasts, such transfer of TatC was made possible due to modifications of the first transmembrane domain. Conclusions At its origin, mitochondria inherited three inner membrane translocases Sec, TAT and Oxa1 (YidC) from its bacterial ancestor. Our work shows for the first time that mitochondrial TAT has likely retained its unique function of transporting folded proteins at least in those few eukaryotes with TatA and TatC subunits encoded in the mitochondrial genome. However, mitochondria, in contrast to chloroplasts, abandoned the machinery multiple times in evolution. The overall lower hydrophobicity of the Oxa1 protein was likely the main reason why this translocase was nearly universally retained in mitochondrial biogenesis pathways

Analysis of diverse eukaryotes suggests the existence of an ancestral mitochondrial apparatus derived from the bacterial type II secretion system

The type 2 secretion system (T2SS) is present in some Gram-negative eubacteria and used to secrete proteins across the outer membrane. Here we report that certain representative heteroloboseans, jakobids, malawimonads and hemimastigotes unexpectedly possess homologues of core T2SS components. We show that at least some of them are present in mitochondria, and their behaviour in biochemical assays is consistent with the presence of a mitochondrial T2SS-derived system (miT2SS). We additionally identified 23 protein families co-occurring with miT2SS in eukaryotes. Seven of these proteins could be directly linked to the core miT2SS by functional data and/or sequence features, whereas others may represent different parts of a broader functional pathway, possibly also involving the peroxisome. Its distribution in eukaryotes and phylogenetic evidence together indicate that the miT2SS-centred pathway is an ancestral eukaryotic trait. Our findings thus have direct implications for the functional properties of the early mitochondrion

XXIV. mezinárodní kolokvium o regionálních vědách

Title in English: 24th International Colloquium on Regional Sciences: Conference proceedings. The conference proceedings consists of papers presented at the 24rd International Colloquium on Regional Sciences that was organized by Department of Regional Economics and Administration FEA MU. It contains 79 articles arranged by topic. The individual articles deal with e.g. socioeconomic disparities among regions, regional policy, territory attractiveness, tourism or regional public administration

XXV. mezinárodní kolokvium o regionálních vědách

Title in English: 25th International Colloquium on Regional Sciences: Conference proceedings The conference proceedings consists of papers presented at the 25th International Colloquium on Regional Sciences that was organized by Department of Regional Economics and Administration FEA MU. It contains 57 articles arranged by topic. The individual articles deal with e.g. socioeconomic disparities among regions, regional policy, territory attractiveness, tourism, or regional public administration

Bacterial proteins in the biogenesis of mitochondria of unicellular eukaryotes.

in English Formation of mitochondria by the conversion of a bacterial endosymbiont is the fundamental moment in the evolution of eukaryotes. An integral part of the organelle genesis was the displacement of the endosymbiont genes to host nucleus and simultaneous creation of new pathways for delivery of proteins synthesized now in the host cytoplasm. Resulting protein translocases are complexes combining original bacterial components and eukaryote-specific proteins. In addition to these novel protein import machines, some components of the original bacterial secretory pathways have remained in the organelle. While the function of a widely distributed mitochondrial homolog of YidC, Oxa1, is well understood, the role of infrequent components of Sec or Tat translocases has not yet been elucidated. So far, more attention has been paid to their abundant plastid homologs, which assemble photosynthetic complexes in the thylakoid membrane. In the thesis, the structure and function of prokaryotic YidC, Sec and Tat machineries and their eukaryotic homologs are described. By comparing both organelles of the endosymbiotic origin, the hypothesis is drawn on why these translocases have been more "evolutionary successful" in plastids than in mitochondria

How Intracellular Pathogens Manipulate Cellular Trafficking.

Mnoho intracelulárních jednobuněčných organismů patří mezi medicínsky významné patogeny člověka. Předmětem této práce budou vybraní parazité - Chlamydia spp., Legionella pneumophila, Trypanosoma cruzi a Toxoplasma gondii - a jejich interakce s vezikulárním transportem hostitelské buňky. Jsou zde popsány základní dráhy vezikulárního transportu a jeho důležité molekuly. Dále pak efektorové proteiny patogenů, které s popsanými molekulami interagují. Zvláštní kapitola je věnována fenoménu mimetování SNARE proteinů bakteriemi. Závěrem je uvedena kapitola o SNARE homologu L. pneumophila, který byl nalezen v naší laboratoři a který je předmětem mojí výzkumné práce.Many intracellular single-celled organisms belong to medically important human pathogens. The selected parasites are subject of this thesis - Chlamydia spp., Legionella pneumophila, Trypanosoma cruzi and Toxoplasma gondii - as well as their interactions with the vesicular transport of the host cell. Basic pathways of vesicular transport are delineated and important participating molecules described. Furthermore, the effector proteins of pathogens that interact with these molecules are included. The special chapter is devoted to phenomenon of mimetics of SNARE proteins by bacteria. The manuscript concludes with a chapter on LpSNARE of Legionella pneumophila, which was found in our laboratory and which is a topic of my experimental work herein.Katedra parazitologieDepartment of ParasitologyPřírodovědecká fakultaFaculty of Scienc

Bacterial proteins in the biogenesis of mitochondria of unicellular eukaryotes.

in English Formation of mitochondria by the conversion of a bacterial endosymbiont is the fundamental moment in the evolution of eukaryotes. An integral part of the organelle genesis was the displacement of the endosymbiont genes to host nucleus and simultaneous creation of new pathways for delivery of proteins synthesized now in the host cytoplasm. Resulting protein translocases are complexes combining original bacterial components and eukaryote-specific proteins. In addition to these novel protein import machines, some components of the original bacterial secretory pathways have remained in the organelle. While the function of a widely distributed mitochondrial homolog of YidC, Oxa1, is well understood, the role of infrequent components of Sec or Tat translocases has not yet been elucidated. So far, more attention has been paid to their abundant plastid homologs, which assemble photosynthetic complexes in the thylakoid membrane. In the thesis, the structure and function of prokaryotic YidC, Sec and Tat machineries and their eukaryotic homologs are described. By comparing both organelles of the endosymbiotic origin, the hypothesis is drawn on why these translocases have been more "evolutionary successful" in plastids than in mitochondria

Bakteriální proteiny v biogenezi mitochondrií jednobuněčných eukaryot.

v češtině Vznik mitochondrie z bakteriálního endosymbionta se řadí mezi zásadní momenty v evoluci eukaryot. Nedílnou součástí organelogeneze byl přesun genů endosymbionta do jádra hostitele a zároveň probíhající tvorba translokačních drah pro proteiny nově syntetizované v cytoplasmě hostitele. Výsledné komplexy translokáz jsou kombinací původních bakteriálních komponent a proteinů specifických pro eukaryota. Kromě translokáz určených pro import proteinů z cytoplazmy najdeme v současných mitochondriích i některé komponenty původních bakteriálních sekrečních drah. Zatímco funkce široce rozšířeného mitochondriálního homologu YidC, Oxa1, je dobře známá, role ojedinělých mitochondriálních Sec a Tat translokáz nebyla zatím objasněna. Více pozornosti bylo zatím věnováno jejich homologům v plastidech, kde se tyto translokázy podílejí na sestavování fotosyntetických komplexů. V této práci jsou shrnuty dosavadní poznatky o struktuře a funkci prokaryotických YidC, Sec a Tat translokáz a jejich eukaryotických homologů. Na základě porovnání obou organel endosymbiotického původu je navržena hypotéza o příčinách větší "evoluční úspěšnosti" v integraci bakteriálních translokáz do transportních drah plastidu.in English Formation of mitochondria by the conversion of a bacterial endosymbiont is the fundamental moment in the evolution of eukaryotes. An integral part of the organelle genesis was the displacement of the endosymbiont genes to host nucleus and simultaneous creation of new pathways for delivery of proteins synthesized now in the host cytoplasm. Resulting protein translocases are complexes combining original bacterial components and eukaryote-specific proteins. In addition to these novel protein import machines, some components of the original bacterial secretory pathways have remained in the organelle. While the function of a widely distributed mitochondrial homolog of YidC, Oxa1, is well understood, the role of infrequent components of Sec or Tat translocases has not yet been elucidated. So far, more attention has been paid to their abundant plastid homologs, which assemble photosynthetic complexes in the thylakoid membrane. In the thesis, the structure and function of prokaryotic YidC, Sec and Tat machineries and their eukaryotic homologs are described. By comparing both organelles of the endosymbiotic origin, the hypothesis is drawn on why these translocases have been more "evolutionary successful" in plastids than in mitochondria.Katedra parazitologieDepartment of ParasitologyFaculty of SciencePřírodovědecká fakult

Analýza parametrů sazenic lesních dřevin z hlediska atraktivity pro prase divoké (Sus scrofa L.)

Increasing population of wild boar correlate with increasing damage not only on agricultural lands on crops or grasslands, but also in forests. This damage is mainly on new forest tree plantations which in no way contributes to the successful restoration of clearings after the bark beetle calamity and has a negative impact on the economy. This diploma thesis describes possible influences that may affect the plants attractiveness for wild boar and their damage. An inventory of plants damage was carried out on randomly selected areas in the areas of southern, central and eastern Moravia. A series of experiments with plantings was also performed on the experimental area in the Moravský Krumlov game reserve, where the behaviour of pigs towards these plantings was monitored by the analysis of damaged seedlings and also from pictures taken by photo traps. Obtained inventory data showed us that the wild boar preferred containerized seedlings and deciduous tree species however the experimental system planting did not show a preference for the root system. Seedlings damage was demonstrated in the vast majority only by pulling or rooting without damaging the root system. In terms of time the seedlings were most damaged in the first week after planting, then the risk of damage decreased. To reduce the risk of disturbance by pigs on plantings a method of protection against this damage is not known yet, so the most effective solution remains to reduce the population of wild boar in affected areas