Analysis of Post-Translational Modifications of a Critical Protein Implicated in Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease in which mutations in human Cu, Zn Superoxide Dismutase (SOD1) have been identified as a cause of familial ALS (FALS) cases.1-2 It has been shown that mutant SOD1 develops a novel toxic function through experiments demonstrating that many disease mutants maintain enzymatic activity, SOD1-null mice do not exhibit ALS symptoms, and co-expressed wild type protein does not rescue the disease-state.7-11 The majority of cases, however, are not caused directly by mutations of SOD1, instead being caused by a poorly understood interplay of several genes as well as environmental factors, which is often referred to as sporadic ALS (SALS).3 It has been found that FALS and SALS share similar pathology. 4-6 The hSOD1 protein aggregates characteristic of FALS have also been found in SALS patients, furthering the evidence that hSOD1 has an important role in the etiology of ALS in sporadic ALS patients.16-19 The exact mechanism of SOD1-associated toxicity has not yet been elucidated though many disease mutants have been shown to destabilize the SOD1 dimer. In this study we aim to compare the levels of SOD1 post-tra slational modifications in ALS patients to levels in healthy donors and to determine if there are distinct patterns of protein glutathionylation or phosphorylation. Our overall goal is to elucidate a direct mechanism of toxicity in SALS as well as identify potentially critical triggers