ERAL1 is associated with mitochondrial ribosome and elimination of ERAL1 leads to mitochondrial dysfunction and growth retardation.
ERAL1, a homologue of Era protein in Escherichia coli, is a member of conserved GTP-binding proteins with RNA-binding activity. Depletion of prokaryotic Era inhibits cell division without affecting chromosome segregation. Previously, we isolated ERAL1 protein as one of proteins which were associated with mitochondrial transcription factor A by using immunoprecipitation. In this study, we analysed the localization and function of ERAL1 in mammalian cells. ERAL1 was localized in mitochondrial matrix and associated with mitoribosomal proteins including the 12S rRNA. siRNA knockdown of ERAL1 decreased mitochondrial translation, caused redistribution of ribosomal small subunits and reduced 12S rRNA. The knockdown of ERAL1 in human HeLa cells elevated mitochondrial superoxide production and slightly decreased mitochondrial membrane potential. The knockdown inhibited the growth of HeLa cells with an accumulation of apoptotic cells. These results suggest that ERAL1 is localized in a small subunit of the mitochondrial ribosome, plays an important role in the small ribosomal constitution, and is also involved in cell viability.
Uchiumi
Takeshi
T
Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Graduate School of Medical Sciences, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. uchiumi@cclm.med.kyushu-u.ac.jp
Ohgaki
Kippei
K
Yagi
Mikako
M
Aoki
Yoshimasa
Y
Sakai
Aya
A
Matsumoto
Shinya
S
Kang
Dongchon
D
D017209:Apoptosis; D049109:Cell Proliferation; D003576:Electron Transport Complex IV / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D014176:Protein Biosynthesis; D012313:RNA / Q000302:isolation & purification; D000077278:RNA, Mitochondrial; D016601:RNA-Binding Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D017382:Reactive Oxygen Species; D054682:Ribosome Subunits, Small, Eukaryotic / Q000378:metabolism*
D024101:Mitochondrial Proteins; D000077278:RNA, Mitochondrial; D016601:RNA-Binding Proteins; D017382:Reactive Oxygen Species; D012313:RNA; D003576:Electron Transport Complex IV; C552417:ERAL1 protein, human; D019204:GTP-Binding Proteins