Formation of a Stabilized Cysteine Sulfinic Acid Is Critical for the Mitochondrial Function of the Parkinsonism Protein DJ-1

Abstract

The formation of cysteine-sulfinic acid has recently become appreciated as a modification that links protein function to cellular oxidative status. Human DJ-1, a protein associated with inherited parkinsonism, readily forms cysteine-sulfinic acid at a conserved cysteine residue (Cys 106 in human DJ-1). Mutation of Cys 106 causes the protein to lose its normal protective function in cell culture and model organisms. However, it is unknown whether the loss of DJ-1 protective function in these mutants is due to the absence of Cys 106 oxidation or the absence of the cysteine residue itself. To address this question, we designed a series of substitutions at a proximal glutamic acid residue (Glu 18 ) in human DJ-1 that alter the oxidative propensity of Cys 106 through changes in hydrogen bonding. We show that two mutations, E18N and E18Q, allow Cys 106 to be oxidized to Cys 106 -sulfinic acid under mild conditions. In contrast, the E18D mutation stabilizes a cysteine-sulfenic acid that is readily reduced to the thiol in solution and in vivo. We show that E18N and E18Q can both partially substitute for wild-type DJ-1 using mitochondrial fission and cell viability assays. In contrast, the oxidatively impaired E18D mutant behaves as an inactive C106A mutant and fails to protect cells. We therefore conclude that formation of Cys 106 -sulfinic acid is a key modification that regulates the protective function of DJ-1.Reactive cysteine residues are susceptible to a variety of covalent modifications that are increasingly recognized as a major means of regulating the activities of many proteins (1). Cysteine forms three different species by the direct addition of oxygen; cysteine-sulfenic (-SOH), -sulfinic (-SO 2 H), and -sulfonic (-SO 3 H) acid. Because cysteine can be oxidized to three distinct species, each with different structural and chemical properties, cysteine oxidation is a versatile way for reactive oxygen species (ROS) 4 to alter the activity of a protein.Of the three oxidation products of cysteine, only cysteine-sulfenic acid is readily reduced to the thiol under physiological conditions. However, enzymes that catalyze the ATP-dependent reduction of overoxidized peroxiredoxins containing cysteine-sulfinic acid to cysteine have been discovered and characterized (2, 3). With reversibility comes the potential for cysteine-sulfinic acid modifications to modulate the function of various target proteins in a redox-dependent manner. Therefore, at least in some proteins, cysteine-sulfinic acid should be regarded as a post-translational modification rather than simply a type of protein damage.As expected, many of the proteins that are modified by cysteine oxidation are involved in the oxidative stress response or in the maintenance of cellular redox homeostasis. Of these proteins, DJ-1 has special importance in understanding the role of regulatory cysteine oxidation in neuronal survival. Loss of function mutations in DJ-1 are a rare cause of early onset recessive parkinsonism (4, 5), although the exact function of DJ-1 i...

Effect of Single Amino Acid Substitution on Oxidative Modifications of the Parkinson’s Disease-Related Protein, DJ-1

“…In support of this idea, a recent study revealed that M26I pretreated with H 2 O 2 inhibited aSyn fibril formation less efficiently than the oxidized wild-type protein (38). Additional evidence suggests that the oxidation of DJ-1 at position 106 is necessary for protection against toxicity related to complex I inhibition (Liu and Rochet, unpublished data) (30). Accordingly, we infer that the decreased propensity of M26I to undergo conversion to the 2O form as reported here may result in various functional defects in familial PD patients, including a reduced ability of the protein to carry out a chaperone function in cytosolic and/or mitochondrial compartments.…”

“…In contrast, other mutations have a less pronounced effect on DJ-1 stability, and it is unclear how they perturb DJ-1 function. In this study we addressed the hypothesis that the M26I familial mutant exhibits reduced protective activity as a result of (1) a decreased ability to undergo oxidation to the functionally important 2O form (16,24,30), and/or (2) an increased propensity to undergo oxidative modifications with potentially disruptive effects on DJ-1 function at other sites in the polypeptide chain.…”

Dopamine-derived Quinones Affect the Structure of the Redox Sensor DJ-1 through Modifications at Cys-106 and Cys-53

“…The oxidation of the highly conserved Cys-106 to cysteine-sulfinic acid has been proposed as a key signaling mechanism to control DJ-1 mitochondria localization in response to oxidative stress. Specifically, the abilities of DJ-1 mutants to oxidize, translocate to mitochondria in response to oxidation, and protect against toxicity are correlated (25,47). The formation of cysteine-sulfinic acid would also justify the pI shift from 6.2 to 5.8 observed upon exposure of DJ-1 to oxidative insults.…”

The Redox Biochemistry of Protein Sulfenylation and Sulfinylation

“…The highly conserved Glu-18 residue facilitates the ionization of Cys-106, reduces its pK a , and helps to stabilize Cys-106-SO 2 H through the formation of an unusually short and consequently strong hydrogen bond (67). Wilson and co-workers (68) have shown that small changes in this position can drastically influence the (69). Considering the high propensity of Cys-106 to oxidize, it has been proposed that DJ-1 acts merely as a direct ROS scavenger.…”