Seminal demonstration that deleting the primary mitochondrial MnSOD sod-2 extends C. elegans lifespan despite increased protein oxidative damage and heightened sensitivity to oxidative stress, directly challenging the oxidative-damage theory of aging. sod-2 mutants phenocopy long-lived mitochondrial mutants (slow development, small brood, reduced respiration).

SOD-2-generated hydrogen peroxide acts as a positive signaling molecule required for sperm pseudopod extension during activation; sod-2 (not sod-1) is the specific SOD required, linking SOD-2 enzymatic output to fertility.

Proposes the RAS-dependent ROS signaling (RDRS) mechanism for sod-2 longevity: loss of SOD-2 raises mitochondrial superoxide, which is converted by cytosolic SOD-1 to hydrogen peroxide that oxidizes a redox-sensitive cysteine of LET-60/RAS, driving a global developmental gene-expression program; the lifespan extension requires SOD-1.

High-throughput direct-assay (mass-spectrometry) source underlying the GOA mitochondrion localization annotation for SOD-2. The cached abstract concerns HAF-1/ClpP-mediated mitochondrial unfolded protein response signalling and does not itself discuss sod-2; the annotation reflects detection of SOD-2 in a mitochondrial proteome dataset.

SOD-2 is the primary mitochondrial superoxide dismutase and co-localizes by blue-native gel with the respiratory supercomplex I:III:IV; loss of SOD-2 specifically lowers complex I and II activity and destabilizes supercomplex formation. sod-2 single mutants have a normal lifespan, but loss of sod-2 can extend the lifespan of some electron-transport-chain mutants.

Cloned sod-2 and sod-3, showed both encode mitochondrial (transit-peptide bearing) manganese-type superoxide dismutases, and directly measured their enzymatic activity after heterologous expression in SOD-deficient E. coli (Mn-type: insensitive to hydrogen peroxide and cyanide; dimeric; protective against paraquat/methyl-viologen oxidative stress).