Diverse microbial ecosystems underpin life in the sea. Among these microbes are many unicellular eukaryotes that span the diversity of the eukaryotic tree of life. However, genetic tractability has been limited to a few species, which do not represent eukaryotic diversity or environmentally relevant taxa. Here, we report on the development of genetic tools in a range of protists primarily from marine environments. We present evidence for foreign DNA delivery and expression in 13 species never before transformed and for advancement of tools for eight other species, as well as potential reasons for why transformation of yet another 17 species tested was not achieved. Our resource in genetic manipulation will provide insights into the ancestral eukaryotic lifeforms, general eukaryote cell biology, protein diversification and the evolution of cellular pathways.
Mitochondrial permeability transition pore (mPTP) opening allows free movement of ions and small molecules leading to mitochondrial membrane depolarization and ATP depletion that triggers cell death. A multi-protein complex of the mitochondrial ATP synthase has an essential role in mPTP. However, the molecular identity of the central 'pore' part of mPTP complex is not known. A highly purified fraction of mammalian mitochondria containing C-subunit of ATPase (C-subunit), calcium, inorganic polyphosphate (polyP) and polyhydroxybutyrate (PHB) forms ion channels with properties that resemble the native mPTP. We demonstrate here that amount of this channel-forming complex dramatically increases in intact mitochondria during mPTP activation. This increase is inhibited by both Cyclosporine A, an inhibitor of mPTP and Ruthenium Red, an inhibitor of the Mitochondrial Calcium Uniporter. Similar increases in the amount of complex formation occurs in areas of mouse brain damaged by ischemia-reperfusion injury. These findings suggest that calcium-induced mPTP is associated with de novo assembly of a channel comprising C-subunit, polyP and PHB.
The cold and menthol receptor TRPM8 is highly expressed in prostate and prostate cancer (PC). Recently, we identified that TRPM8 is as an ionotropic testosterone receptor. The TRPM8 mRNA is expressed in early prostate tumors with high androgen levels, while anti-androgen therapy greatly reduces its expression. Here, from the chromatin-immunoprecipitation (ChIP) analysis, we found that an androgen response element (ARE) mediates androgen regulation of trpm8. Furthermore, using immunofluorescence, calcium-imaging and planar lipid bilayers, we identified that TRPM8 channel is functionally regulated by androgens in the prostate. Although TRPM8 mRNA is expressed at high levels, we found that the TRPM8 protein undergoes ubiquitination and degradation in PC cells. The mass-spectrometry analysis of TRPM8, immunoprecipitated from LNCaP cells identified ubiquitin-like modifier-activating enzyme 1 (UBA1). PYR-41, a potent inhibitor of initial enzyme in the ubiquitination cascade, UBA1, increased TRPM8 activity on the plasma membrane (PM) of LNCaP cells. Furthermore, PYR-41-mediated PMTRPM8 activity was accompanied by enhanced activation of p53 and Caspase-9. Interestingly, we found that the trpm8 promoter possesses putative binding sites for p53 and that the overexpression of p53 increased the TRPM8 mRNA levels. In addition to the genomic regulation of TRPM8 by AR and p53, our findings indicate that the testosterone-induced PMTRPM8 activity elicits Ca2+ uptake, subsequently causing apoptotic cell death. These findings support the strategy of rescuing PMTRPM8 expression as a new therapeutic application through the regulation of PC cell growth and proliferation.
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