Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The . gov means it’s official. Federal government websites often end in . gov or VSports app下载. mil. Before sharing sensitive information, make sure you’re on a federal government site. .

Https

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely. V体育官网.

Review
. 2015 Aug 25:9:336.
doi: 10.3389/fncel.2015.00336. eCollection 2015.

SOD1 misplacing and mitochondrial dysfunction in amyotrophic lateral sclerosis pathogenesis

Affiliations
Review

SOD1 misplacing and mitochondrial dysfunction in amyotrophic lateral sclerosis pathogenesis

"VSports" Francesco Tafuri et al. Front Cell Neurosci. .

Abstract

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease presenting as sporadic (sALS) or familial (fALS) forms. Even if the list of the genes underlining ALS greatly expanded, defects in superoxide dismutase 1 (SOD1), encoding the copper/zinc SOD1, still remain a major cause of fALS and are likely involved also in apparently sporadic presentations. The pathogenesis of ALS is still unknown, but several lines of evidence indicate that the mitochondrial accumulation of mutant SOD1 is an important mechanism of mitochondrial dysfunction, leading to motor neuron pathology and death. The intramitochondrial localization of mutant SOD1 is debated. Mutant SOD1 might accumulate inside the intermembrane space (IMS), overriding the physiological retention regulated by the copper chaperone for superoxide dismutase (CCS). On the other hand, misfolded SOD1 might deposit onto the outer mitochondrial membrane (OMM), clumping the transport across mitochondrial membranes and engaging mitochondrial-dependent cell apoptosis VSports手机版. The elucidation of the mechanisms ruling SOD1 localization and misplacing might shed light on peculiar ALS features such as cell selectivity and late onset. More importantly, these studies might disclose novel targets for therapeutic intervention in familial ALS as well as non-genetic forms. Finally, pharmacological or genetic manipulation aimed to prevent or counteract the intracellular shifting of mutant SOD1 could be effective for other neurodegenerative disorders featuring the toxic accumulation of misfolded proteins. .

Keywords: mitochondria; mitochondrial intermembrane space; motor neuron disorder; outer mitochondrial membrane; protein misfolding; superoxide dismutase 1 V体育安卓版. .

PubMed Disclaimer

Figures

Figure 1
Figure 1
SOD1 function and structure. (A) Electron transport chain locatedin the inner mitochondrial membrane (IMM). (1) and (2) represent the main sources of superoxide anion (O2), a reactive oxygen specie converted to H2O2 in a dismutase reaction catalyzed by SOD (Cu/Zn; SOD1) and SOD (Mn; SOD2) in the intermembrane mitochondrial space (IMS) and matrix, respectively. C I: complex I NADH dehydrogenase. C II: complex II succinate dehydrogenase. C III: complex III ubiquinol cytochrome C oxidoreductase. C IV: complex IV cytochrome C oxidase. C V: complex V ATP synthase. (B) Scheme representing the determinants of tertiary structure of human SOD1, including β sheets (green arrows), α helix (yellow cilinder) and loops. β sheets: β1: 2–8° aa -β2: 15–22° aa -β3: 29–36° aa -β4: 41–48° aa -β5: 83–89° aa -β6: 95–101° aa -β7: 116–120° aa -β8: 143–151° aa. α helix: 134–137° aa. The yellow dots represent residues involved in Cu2+ coordination (His46, His48, His63, His120). The orange dots represent residues involved in Zn2+ coordination (His63, His71, His80, Asp83). The purple dots represent residues involved in disulfide bridge formation (Cys57, Cys146).
Figure 2
Figure 2
Transport of SOD1 across mitochondrial intermembrane space (IMS). SOD1 (unfolded) apo-protein enters IMS through the transporter of outer membrane (TOM). Inside IMS unfolded SOD1 undergoes maturation steps: (1) disulfide bonds promoting a proper folding, (2) the insertion of metal ions Zn and Cu, (3) dimerization. Disulfide bonds formation and prosthetic group insertion are mediated by copper chaperone for superoxide dismutase (CCS). Disulfide bonds prevent SOD1 leakage from mitochondria through TOM. High O2 levels might also induce CCS and SOD1 protein folding in cytoplasm. SOD1, superoxide dismutase 1; CCS, copper chaperone for superoxide dismutase; TOM, translocase of outer membrane; OMM, outer mitochondrial membrane; IMS, intermembrane space.
Figure 3
Figure 3
Accumulation of mutant SOD1 inside IMS and deposition onto OMM. (A) Mutant SOD1 enters IMS through TOM. Inside IMS mutant SOD1 can precipitate in insoluble form (1) or undergo folding via Mia40 resulting in the establishment of funtional homodimers and heterodimers (2). Mia40 transfers electrons to Cytochrome C (CytC) via Erv1 (3). TOM, translocase of outer membrane; OMM, outer mitochondrial membrane; IMS, intermembrane space; IMM, inner mitochondrial membrane; CIV, complex IV cytochrome C oxidase; MutSOD1, mutant SOD1. (B) Misfolded SOD1 localization upon mitochondria can be regulated in different tissue cells. Cytosol composition may differ according cell types. High cytosolic levels of soluble MIF (macrophage migration inhibitory factor) are able to prevent SOD1 mislocalization where its absence favor SOD1 deposition onto OMM. Misfolded SOD1 interactions with OMM proteins, such as Bcl-2 and VDAC, activate pro-apoptotic mitochondrial pathway leading to cell death. This interaction can be prevented by MIF. TOM, translocase of outer membrane; OMM, outer mitochondrial membrane; IMS, intermembrane space; IMM, inner mitochondrial membrane; CIV, complex IV cytochrome C oxidase; MutSOD1, mutant SOD1.

References (VSports)

    1. Ahtoniemi T., Jaronen M., Keksa-Goldsteine V., Goldsteins G., Koistinaho J. P. (2008). Mutant SOD1 from spinal cord of G93A rats is destabilized and binds to inner mitochondrial membrane. Neurobiol. Dis. 32, 479–485. 10.1016/j.nbd.2008.08.010 - DOI - PubMed
    1. Arciello M., Capo C. R., D’Annibale S., Cozzolino M., Ferri A., Carrì M. T., et al. . (2011). Copper depletion increases the mitochondrial-associated SOD1 in neuronal cells. Biometals 24, 269–278. 10.1007/s10534-010-9392-3 - DOI - PubMed
    1. Bailey A. O., Miller T. M., Dong M. Q., Vande Velde C., Cleveland D. W., Yates J. R. (2007). RCADiA: simple automation platform for comparative multidimensional protein identification technology. Anal. Chem. 79, 6410–6418. 10.1021/ac070585g - VSports注册入口 - DOI - PMC - PubMed
    1. Banci L., Bertini I., Boca M., Girotto S., Martinelli M., Valentine J. S., et al. . (2008). SOD1 and amyotrophic lateral sclerosis: mutations and oligomerization. PLoS One 3:e1677. 10.1371/journal.pone.0001677 - DOI - PMC - PubMed
    1. Banci L., Bertini I., Cantini F., Kozyreva T., Massagni C., Palumaa P., et al. . (2012). Human superoxide dismutase 1 (hSOD1) maturation through interaction with human copper chaperone for SOD1 (hCCS). Proc. Natl. Acad. Sci. U S A 109, 13555–13560. 10.1073/pnas.1207493109 - DOI - PMC - PubMed