Project description:Chlorophycean algae of the genera Chlamydomonas and Polytomella share a common photosynthetic ancestor. However, members of the Polytomella lineage have adopted a heterotrophic lifestyle, having lost the photosynthetic apparatus and relying instead on acetate or ethanol as carbon sources, with energy production centered on oxidative phosphorylation (OXPHOS). In this study, we investigated the composition of the mitochondrial supercomplexes of the colorless alga Polytomella parva. Mitochondrial membranes were solubilized using mild detergents such as glycol-diosgenin and digitonin, followed by separation of OXPHOS complexes supramolecular assemblies via Blue Native electrophoresis and Fast Protein Liquid Chromatography (FPLC). Additionally, complexome profiling of solubilized algal mitochondria resolved by Blue Native Gel Electrophoresis was carried out. The resulting data indicate that the OXPHOS supercomplexes of Polytomella closely resemble those observed in situ in the mitochondria of its green relative Chlamydomonas reinhardtii, as revealed by electron cryo-tomography and subtomogram averaging.
Project description:The unicellular, free-living, nonphotosynthetic chlorophycean alga Polytomella parva, closely related to Chlamydomonas reinhardtii and Volvox carteri, contains colorless, starch-storing plastids. The P. parva plastids lack all light-dependent processes but maintain crucial metabolic pathways. The colorless alga also lacks a plastid genome, meaning no transcription or translation should occur inside the organelle. Here, using an algal fraction enriched in plastids as well as publicly available transcriptome data, we provide a proteomic characterization of the P. parva plastid, ultimately identifying several plastid proteins, both by mass spectrometry and bioinformatic analyses. Altogether these results led us to propose a plastid proteome for P. parva, i.e., a set of proteins that participate in carbohydrate metabolism; in the synthesis and degradation of starch, amino acids and lipids; in the biosynthesis of terpenoids and tetrapyrroles; in solute transport and protein translocation; and in redox homeostasis. This is the first detailed plastid proteome from a unicellular, free-living colorless alga.
Project description:Alpha-parvin (PARVA) is known to involve in the linkage of integrins, regulation of actin cytoskeleton dynamics, and cell survival. However, the role of PARVA in cancer progress is still unclear. Here, we identify PARVA as a potential oncogene from a lung cancer invasion cell line model by expression microarrays. Overexpression of PARVA enhances cell invasion, colony formation ability, and endothelial cell tube formation but knockdown of PARVA inhibits invasion and tube formation in vitro. PARVA also promotes tumorigenicity, angiogenesis, metastasis and mortality by in vivo tumorigenesis and metastasis mouse models. To explore the underlying mechanism, the PARVA-regulated signaling pathways were analyzed in PARVA-overexpressing cells compare with mock controls by expression microarrays. We used microarrays to profile the global gene expression of PARVA-overexpressing cells compared with mock control cells and identified the pathways involved in PARVA-induced biofunctional alterations.