SOD1 Lysine 123 Acetylation in the Adult Central Nervous System

Abstract

Superoxide dismutase 1 (SOD1) knockout (Sod1−/−) mice exhibit an accelerated aging phenotype. In humans, SOD1 mutations are linked to familial amyotrophic lateral sclerosis (ALS), and post-translational modification (PTM) of wild-type SOD1 has been associated with sporadic ALS. Reversible acetylation regulates many enzymes and proteomic studies have identified SOD1 acetylation at lysine 123 (K123). The function and distribution of K123-acetylated SOD1 (Ac-K123 SOD1) in the nervous system is unknown. Here, we generated polyclonal rabbit antibodies against Ac-K123 SOD1. Sod1 deletion in Sod1−/− mice, K123 mutation or preabsorption with Ac-K123 peptide all abolished antibody binding. Using immunohistochemistry, we assessed Ac-K123 SOD1 distribution in the normal adult mouse nervous system. In the cerebellum, Ac-K123 SOD1 staining was prominent in cell bodies of the granular cell layer (GCL) and Purkinje cell dendrites and interneurons of the molecular cell layer. In the hippocampus, Ac-K123 SOD1 staining was strong in the fimbria, subiculum, pyramidal cells and Schaffer collateral fibers of the cornus ammonis field 1 (CA1) region and granule and neuronal progenitor cells of the dentate gyrus. In addition, labeling was observed in the choroid plexus (CP) and the ependyma of the brain ventricles and central canal of the spinal cord. In the olfactory bulb, Ac-K123 SOD1 staining was prominent in axons of sensory neurons, in cell bodies of interneurons and neurites of the mitral and tufted cells. In the retina, labeling was strong in the retinal ganglion cell layer (RGCL) and axons of retinal ganglion cells (RGCs), the inner nuclear layer (INL) and cone photoreceptors of the outer nuclear layer (ONL). In summary, our findings describe Ac-K123 SOD1 distribution to distinct regions and cell types of the normal nervous system.

Metallothionein and Superoxide Dismutase—Antioxidative Protein Status in Fullerene-Doxorubicin Delivery to MCF-7 Human Breast Cancer Cells

“…Glutathionylation, palmitoylation, succinylation and acetylation are among the PTMs of SOD1. Lysine 123 acetylation is a reversible PTM that regulates the interaction, subcellular localization, folding and activity of many proteins [ 48 ]. Specific conditions, such as H 2 O 2 and superoxide concentration, appear to favor SOD activity [ 49 ].…”

The biophysics of superoxide dismutase-1 and amyotrophic lateral sclerosis

“…Sirtuin-1 is known to act as a deacetylase for SOD1 Lys70 and restores activation by hCCS (Lin et al ., 2015). Acetylation of Lys122, on the N-terminus of the electrostatic loop, does not change SOD1 activity but is found only in specific cell types and regions within the CNS indicating functional importance (Kaliszewski et al ., 2016). Non-specific lysine acetylation of wild-type, Asp90Ala and Ala4Val SOD1 with aspirin in vitro inhibited the nucleation rate and extension of aggregates overall.…”

Acylation of Superoxide Dismutase 1 (SOD1) at K122 Governs SOD1-Mediated Inhibition of Mitochondrial Respiration

“…Figure 5B shows the increase in endogenous SOD1 succinylation at K122 in SIRT5-depleted cells. Although acetylation of K122 clearly occurs on endogenous SOD1 (21,26,28,30; also our proteomics data), our attempts to generate site-specific acetyl-K122 antibodies had only limited success: the antibodies showed marginal specificity to the acetylation. This complication, combined with the fact that K122E showed a slightly more robust effect in inhibiting the antirespiration function of SOD1 than K122Q, led us to focus primarily on K122 succinylation.…”

“…A study by Lin et al found that SIRT5 desuccinylates K122, and it was proposed to affect SOD1 antioxidant activity (29). In addition, a recent study using a site-specific antibody demonstrated that K122 is acetylated on endogenous SOD1 in multiple cell types throughout the murine nervous system (30), although the impact of the acetyl modification on SOD1 function was not demonstrated. With this background, we investigated the functional impact of K122 acylation on SOD1.…”