Publications by authors named "Chiranjit Panja"

Even if a myriad of approaches has been developed to identify the subcellular localization of a protein, the easiest and fastest way remains to fuse the protein to Green Fluorescent Protein (GFP) and visualize its location using fluorescence microscopy. However, this strategy is not well suited to visualize the organellar pools of proteins that are simultaneously localized both in the cytosol and in organelles because the GFP signal of a cytosolic pool of the protein (cytosolic echoform) will inevitably mask or overlay the GFP signal of the organellar pool of the protein (organellar echoform). To solve this issue, we engineered a dedicated yeast strain expressing a Bi-Genomic Mitochondrial-Split-GFP.

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Reactive oxygen species (ROS), play important roles in cellular signaling, nonetheless are toxic at higher concentrations. Cells have many interconnected, overlapped or backup systems to neutralize ROS, but their regulatory mechanisms remain poorly understood. Here, we reveal an essential role for mitochondrial AMPylase Fmp40 from budding yeast in regulating the redox states of the mitochondrial 1-Cys peroxiredoxin Prx1, which is the only protein shown to neutralize HO with the oxidation of the mitochondrial glutathione and the thioredoxin Trx3, directly involved in the reduction of Prx1.

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Defects in ATP synthase functioning due to the substitutions in its two mitochondrially encoded subunits a and 8 lead to untreatable mitochondrial diseases. Defining the character of variants in genes encoding these subunits is challenging due to their low frequency, heteroplasmy of mitochondrial DNA in patients' cells and polymorphisms of mitochondrial genome. We successfully used yeast S.

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Article Synopsis
  • The study highlights the increasing number of mitochondrial DNA (mtDNA) variants linked to neurodegenerative diseases and the challenges in assessing their impact, especially when present alongside normal mtDNA.
  • Saccharomyces cerevisiae (yeast) is utilized as a model organism to analyze the effects of specific mtDNA variants on mitochondrial function due to its ability to support genetic transformations and similar mitochondrial protein function.
  • Out of eight investigated MT-ATP6 gene variants in yeast, three variants (m.8950G>A, m.9025G>A, and m.9029A>G) showed significant defects in growth and ATP production, indicating potential pathogenicity, while the other five variants had little to no effect on mitochondrial function.
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The mitochondrial ATP synthase, an enzyme that synthesizes ATP and is involved in the formation of the mitochondrial mega-channel and permeability transition, is a multi-subunit complex. In S. cerevisiae, the uncharacterized protein Mco10 was previously found to be associated with ATP synthase and referred as a new 'subunit l'.

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Article Synopsis
  • The m.9032T>C mitochondrial DNA mutation has been linked to NARP, causing reduced ATP synthesis and increased oxidative stress in affected patients.
  • This mutation results in a critical amino acid change (L169P) in ATP synthase, impairing its function in transporting protons for ATP production.
  • Research using a yeast model with a similar mutation (L186P) showed that while the enzyme assembled properly, it was largely inactive, but intragenic suppressors were found that partially restored its function.
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Article Synopsis
  • Many diseases in humans are linked to mutations in the mitochondrial genome (mtDNA), which is crucial for producing energy through oxidative phosphorylation (OXPHOS).
  • mtDNA mutations can have severe effects, particularly in energy-demanding tissues, and their pathogenicity is complicated by the phenomenon of heteroplasmy, where a cell contains a mix of mutant and normal mitochondrial DNA.
  • The yeast Saccharomyces cerevisiae serves as an effective model to study these human mtDNA mutations since it allows for genome manipulation and offers insights into the consequences of specific mutations on energy production and potential therapeutic discoveries.
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Background/aims: Mitochondrial ATP synthase, in addition to being involved in ATP synthesis, is involved in permeability transition pore (PTP) formation, which precedes apoptosis in mammalian cells and programmed cell death in yeast. Mutations in genes encoding ATP synthase subunits cause neuromuscular disorders and have been identified in cancer samples. PTP is also involved in pathology.

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The biological outcome of nitric oxide (NO) and reactive nitrogen species (RNS) in regulating pro survival and pro death autophagic pathways still demand further investigation. In the present study, we investigated the effect of nitrosative stress in K562 cells using NO donor compound DETA-NONOate, peroxynitrite, and SIN-1. Exposure to NO, peroxynitrite, and SIN-1 caused decrease in K562 cell survival.

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Yeast flavohemoglobin, YHb, encoded by the nuclear gene YHB1, has been implicated in the nitrosative stress responses in Saccharomyces cerevisiae. It is still unclear how S. cerevisiae can withstand this NO level in the absence of flavohemoglobin.

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Protein tyrosine nitration (PTN) is a selective post-translational modification often associated with physiological and pathophysiological conditions. Tyrosine is modified in the 3-position of the phenolic ring through the addition of a nitro group. In our previous study we first time showed that PTN occurs in vivo in Saccharomyces cerevisiae.

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