Submitted on January 9, 2004
Accepted on September 21, 2004
Overexpression of Mutated Cu, Zn-SOD in Neuroblastoma Cells Results in Cytoskeletal Change
Rina Takamiya1, Motoko Takahashi1, Yong Seek Park1, Yoshie Tawara1, Noriko Fujiwara2, Yasuhide Miyamoto1, Jianguo Gu1, Keiichiro Suzuki2, and Naoyuki Taniguchi1*
1 Department of Biochemistry, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
2 Department of Biochemistry, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
* To whom correspondence should be addressed. E-mail: proftani{at}biochem.med.osaka-u.ac.jp.
Amyotrophic lateral sclerosis (ALS) involves the progressive degeneration of motor neurons in the spinal cord and motor cortex. It has been shown that 15-20% of patients with familial ALS (FALS) have defects in the Sod1 gene which encodes Cu, Zn-superoxide dismutase (SOD). To elucidate the pathological role of mutated Cu, Zn-SODs, we examined the issue of whether mutated Cu, Zn-SOD affects the cell cycle. Mouse neuroblastoma Neuro-2a cells were transfected with human wild-type or mutated (G37R, G93A) Cu, Zn-SODs. Mutated Cu, Zn-SOD transfected cells exhibited a marked retardation in cell growth and G2/M arrest. They also displayed a lower reactivity to phalloidin, indicating that the cytoskeleton was disrupted. Immunoprecipitation, 2-D gel electrophoresis and Western blotting analysis indicate that the mutated Cu, Zn-SODs associate with actin. Similar results were obtained by in vitro incubation experiments with purified actin and mutated Cu, Zn-SOD (G93A). These results suggest that mutated Cu, Zn-SODs in FALS cause cytoskeletal changes by associating with actin, subsequently causing G2/M arrest and growth retardation.
