Work

AKR1A1 is a novel mammalian S-nitroso-glutathione reductase

Year: 2019

Type: article

Abstract: Oxidative modification of Cys residues by NO results in S -nitrosylation, a ubiquitous post-translational modification and a primary mediator of redox-based cellular signaling. Steady-state levels of S -nitrosylated proteins are largely determined by denitrosylase enzymes that couple NAD(P)H oxidation with reduction of S -nitrosothiols, including protein and low-molecular-weight (LMW) S -nitrosothiols ( S -nitroso-GSH (GSNO) and S -nitroso-CoA (SNO-CoA)). SNO-CoA reductases require NADPH, whereas enzymatic reduction of GSNO can involve either NADH or NADPH. Notably, GSNO reductase (GSNOR, Adh5 ) accounts for most NADH-dependent GSNOR activity, whereas NADPH-dependent GSNOR activity is largely unaccounted for (CBR1 mediates a minor portion). Here, we de novo purified NADPH-coupled GSNOR activity from mammalian tissues and identified aldo-keto reductase family 1 member A1 (AKR1A1), the archetypal mammalian SNO-CoA reductase, as a primary mediator of NADPH-coupled GSNOR activity in these tissues. Kinetic analyses suggested an AKR1A1 substrate preference of SNO-CoA > GSNO. AKR1A1 deletion from murine tissues dramatically lowered NADPH-dependent GSNOR activity. Conversely, GSNOR-deficient mice had increased AKR1A1 activity, revealing potential cross-talk among GSNO-dependent denitrosylases. Molecular modeling and mutagenesis of AKR1A1 identified Arg-312 as a key residue mediating the specific interaction with GSNO; in contrast, substitution of the SNO-CoA–binding residue Lys-127 minimally affected the GSNO-reducing activity of AKR1A1. Together, these findings indicate that AKR1A1 is a multi-LMW-SNO reductase that can distinguish between and metabolize the two major LMW-SNO signaling molecules GSNO and SNO-CoA, allowing for wide-ranging control of protein S -nitrosylation under both physiological and pathological conditions.

Source: Journal of Biological Chemistry

DOI: 10.1074/jbc.ra119.011067