Effects of heterologous expression of human cyclic nucleotide phosphodiesterase 3A (hPDE3A) on redox regulation in Yeast

Monday, September 22, 2014 — Poster Session II
4:00 p.m. – 6:00 p.m.	FAES Academic Center	NHLBI	MOLBIO-15

Authors

• DK Rhee
• JC Lim
• S Hockman
• F Ahmad
• YW Chung
• S Liu
• A Hockman
• V Manganiello

Abstract

PDEs are components of RAS/cAMP signaling pathways involved in regulation of oxidative stress, and, in S. cerevisiae, we studied effects of exogenous WT human (h)PDE3A and K13R hPDE3A (a putative ubiquitinylation site mutant) on H2O2-induced oxidative stress. H2O2-stimulated ROS production was markedly increased in yeast expressing K13R hPDE3A, named OxiS1, compared to that in mock or yeast expressing WT hPDE3A, named OxiR1. In OxiR1, H2O2-induced ROS production was reduced, and YAP1 and YAP1-dependent anti-oxidant genes were upregulated and accompanied by reduction of Tsa1p. However, in OxiS1, accumulation of YAP1 and YAP1-dependent genes was greatly reduced, resulting in failure to recover from oxidative stress. H2O2 increased ubiquitinylation, phosphorylation, and activity of WT hPDE3A, but not K13R hPDE3A. Despite differences in PDE activities, PKA activity was increased in OxiR1 and mock, but was lower in OxiS1. During H2O2-treatment, activity of Sch9p, a TORC1-regulated rpS6 kinase and negative regulator of PKA, was rapidly reduced in OxiR1, but maintained in OxiS1, consistent with reduced PKA activity and reduced phosphorylation of PKA substrates in OxiS1. Thus, during oxidative stress, PKA activity may be regulated by TOR-Sch9 signaling, and post-translational modifications of hPDE3A may be critical in its regulation of cellular recovery.

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