Role of Protein Phosphatase 1 and Inhibitor of Protein Phosphatase 1 in Nitric Oxide-Dependent Inhibition of the DNA Damage Response in Pancreatic β-Cells. Diabetes 2018 May;67(5):898-910
Date
02/16/2018Pubmed ID
29444892Pubmed Central ID
PMC5909998DOI
10.2337/db17-1062Scopus ID
2-s2.0-85046011042 (requires institutional sign-in at Scopus site) 7 CitationsAbstract
Nitric oxide is produced at micromolar levels by pancreatic β-cells during exposure to proinflammatory cytokines. While classically viewed as damaging, nitric oxide also activates pathways that promote β-cell survival. We have shown that nitric oxide, in a cell type-selective manner, inhibits the DNA damage response (DDR) and, in doing so, protects β-cells from DNA damage-induced apoptosis. This study explores potential mechanisms by which nitric oxide inhibits DDR signaling. We show that inhibition of DDR signaling (measured by γH2AX formation and the phosphorylation of KAP1) is selective for nitric oxide, as other forms of reactive oxygen/nitrogen species do not impair DDR signaling. The kinetics and broad range of DDR substrates that are inhibited suggest that protein phosphatase activation may be one mechanism by which nitric oxide attenuates DDR signaling in β-cells. While protein phosphatase 1 (PP1) is a primary regulator of DDR signaling and an inhibitor of PP1 (IPP1) is selectively expressed only in β-cells, disruption of either IPP1 or PP1 does not modify the inhibitory actions of nitric oxide on DDR signaling in β-cells. These findings support a PP1-independent mechanism by which nitric oxide selectively impairs DDR signaling and protects β-cells from DNA damage-induced apoptosis.
Author List
Oleson BJ, Naatz A, Proudfoot SC, Yeo CT, Corbett JAAuthor
John A. Corbett PhD Chair, Professor in the Biochemistry department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsApoptosis
Cell Survival
DNA Damage
Histones
Insulin-Secreting Cells
Nitric Oxide
Nitric Oxide Donors
Phosphoproteins
Phosphorylation
Protein Phosphatase 1
Proteins
Rats
Signal Transduction
