Dorfin-CHIP chimeric proteins potently ubiquitylate and degrade familial ALS-related mutant SOD1 proteins and reduce their cellular toxicity.
The ubiquitin-proteasome system (UPS) is involved in the pathogenetic mechanisms of neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). Dorfin is a ubiquitin ligase (E3) that degrades mutant SOD1 proteins, which are responsible for familial ALS. Although Dorfin has potential as an anti-ALS molecule, its life in cells is short. To improve its stability and enhance its E3 activity, we developed chimeric proteins containing the substrate-binding hydrophobic portion of Dorfin and the U-box domain of the carboxyl terminus of Hsc70-interacting protein (CHIP), which has strong E3 activity through the U-box domain. All the Dorfin-CHIP chimeric proteins were more stable in cells than was wild-type Dorfin (Dorfin(WT)). One of the Dorfin-CHIP chimeric proteins, Dorfin-CHIP(L), ubiquitylated mutant SOD1 more effectively than did Dorfin(WT) and CHIP in vivo, and degraded mutant SOD1 protein more rapidly than Dorfin(WT) does. Furthermore, Dorfin-CHIP(L) rescued neuronal cells from mutant SOD1-associated toxicity and reduced the aggresome formation induced by mutant SOD1 more effectively than did Dorfin(WT).
Ishigaki
Shinsuke
S
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8500, Japan.
Niwa
Jun-ichi
J
Yamada
Shin-ichi
S
Takahashi
Miho
M
Ito
Takashi
T
Sone
Jun
J
Doyu
Manabu
M
Urano
Fumihiko
F
Sobue
Gen
G
D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D051379:Mice; D009154:Mutation / Q000235:genetics; D009410:Nerve Degeneration / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D009498:Neurotoxins / Q000037:antagonists & inhibitors / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity; D000072105:Superoxide Dismutase-1; D025801:Ubiquitin / Q000819:agonists / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
D004268:DNA-Binding Proteins; D009498:Neurotoxins; D011993:Recombinant Fusion Proteins; C000606290:SOD1 protein, human; D025801:Ubiquitin; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; C423571:RNF19A protein, human; C467728:STUB1 protein, human; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex