Project description:In this work, we show that under specific conditions, defect in AMP deaminase activity strongly impairs yeast cell growth and we establish that AMP deaminase is required for correct balance between adenylic and guanylic nucleotides. Study of the Amd1p homologs, Yjl070p and Ybr284p, reveals that overexpression of these proteins cannot suppress phenotypes associated to /amd1/ deletion but instead mimic in a wild-type strain a loss of Amd1p function. Data presented combined global transcription analyses to measurements of intracellular nucleotides pools by HPLC. Keywords: yeast strains implied in purines interconversion.
Project description:In this work, we show that under specific conditions, defect in AMP deaminase activity strongly impairs yeast cell growth and we establish that AMP deaminase is required for correct balance between adenylic and guanylic nucleotides. Study of the Amd1p homologs, Yjl070p and Ybr284p, reveals that overexpression of these proteins cannot suppress phenotypes associated to /amd1/ deletion but instead mimic in a wild-type strain a loss of Amd1p function. Data presented combined global transcription analyses to measurements of intracellular nucleotides pools by HPLC. Keywords: yeast strains implied in purines interconversion. 4 biological samples in dye-swap.
Project description:Adenine nucleotides represent crucial immunomodulators in the extracellular environment. The ectonucleotidases CD39 and CD73 are responsible for the sequential catabolism of ATP to adenosine via AMP, thereby promoting an anti-inflammatory milieu induced by the “adenosine halo”. AMPD2 intracellularly mediates AMP deamination to IMP, thus constituting an ambiguous mediator both enhancing the degradation of inflammatory ATP and reducing the formation of protective adenosine. Here, we show that this enzyme is expressed on the cell surface of human immune cells and its predominance may[BF1] modify inflammatory states by altering the extracellular milieu. Surface AMPD2 (eAMPD2) expression on monocytes was verified by immunoblot, mass spectrometry, surface biotinylation, and immunofluorescence microscopy. Flow cytometry revealed enhanced monocytic eAMPD2 expression after TLR stimulation. PBMCs from patients with rheumatoid arthritis displayed significantly higher levels of eAMPD2 expression compared to healthy controls. Furthermore, we observed that extracellular adenosine production was not impaired by an enhanced eAMPD2 expression, while IMP exerted anti-inflammatory effects. In summary, our study identifies eAMPD2 as a novel regulator of the extracellular ATP-adenosine balance adding to the immunomodulatory CD39-CD73 system.
