UniProt functional annotation for P00441

UniProt code: P00441.

Organism: Homo sapiens (Human).
Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.
 
Function: Destroys radicals which are normally produced within the cells and which are toxic to biological systems.
 
Catalytic activity: 2 superoxide + 2 H(+) = O(2) + H(2)O(2).
Cofactor: Binds 1 copper ion per subunit.
Cofactor: Binds 1 zinc ion per subunit.
Subunit: Homodimer; non-disulfide linked. Homodimerization may take place via the ditryptophan cross-link at Trp-33. The pathogenic variants ALS1 Arg-38, Arg-47, Arg-86 and Ala-94 interact with RNF19A, whereas wild-type protein does not. The pathogenic variants ALS1 Arg-86 and Ala-94 interact with MARCH5, whereas wild-type protein does not.
Subcellular location: Cytoplasm. Nucleus. Note=Predominantly cytoplasmic; the pathogenic variants ALS1 Arg-86 and Ala-94 gradually aggregates and accumulates in mitochondria.
Ptm: Unlike wild-type protein, the pathogenic variants ALS1 Arg- 38, Arg-47, Arg-86 and Ala-94 are polyubiquitinated by RNF19A leading to their proteasomal degradation. The pathogenic variants ALS1 Arg-86 and Ala-94 are ubiquitinated by MARCH5 leading to their proteasomal degradation.
Ptm: The ditryptophan cross-link at Trp-33 is responsible for the non-disulfide-linked homodimerization. Such modification might only occur in extreme conditions and additional experimental evidence is required.
Ptm: Palmitoylation helps nuclear targeting and decreases catalytic activity.
Ptm: Succinylation, adjacent to copper catalytic site probably inhibit activity. Desuccinylated by SIRT5, enhancing activity.
Disease: Amyotrophic lateral sclerosis 1 (ALS1) [MIM:105400]: A neurodegenerative disorder affecting upper motor neurons in the brain and lower motor neurons in the brain stem and spinal cord, resulting in fatal paralysis. Sensory abnormalities are absent. The pathologic hallmarks of the disease include pallor of the corticospinal tract due to loss of motor neurons, presence of ubiquitin-positive inclusions within surviving motor neurons, and deposition of pathologic aggregates. The etiology of amyotrophic lateral sclerosis is likely to be multifactorial, involving both genetic and environmental factors. The disease is inherited in 5- 10% of the cases. Note=The disease is caused by mutations affecting the gene represented in this entry.
Miscellaneous: The protein (both wild-type and ALS1 variants) has a tendency to form fibrillar aggregates in the absence of the intramolecular disulfide bond or of bound zinc ions. These aggregates may have cytotoxic effects. Zinc binding promotes dimerization and stabilizes the native form.
Similarity: Belongs to the Cu-Zn superoxide dismutase family.

Annotations taken from UniProtKB at the EBI.