Oxidative stress-induced ubiquitination of RCAN1 mediated by SCFbeta-TrCP ubiquitin ligase.
A change in the protein level of RCAN1 (DSCR1/MCIP/Adapt78/CSP1) has been implicated in oxidative stress-induced cell death in neurons and in the pathogenesis of Alzheimer's disease. The pathogenic processes in neurodegenerative diseases are closely related to oxidative stress and the ubiquitin proteasome system (UPS). Therefore, we investigated whether oxidative stress induces a change in the protein level of RCAN1 through the UPS. H2O2 induced ubiquitination of RCAN1 at the same concentrations as those causing a decrease in RCAN1 in HEK293T cells. beta-TrCP, the F-box protein component of SCF ubiquitin ligase, interacted with RCAN1 in response to H2O2 stimulation. Although FBW4, another F-box protein, interacted with RCAN1, its interaction was independent of H2O2 stimulation. In vitro ubiquitination assay showed that SCFbeta-TrCP but not SCFFBW4 increased ubiquitination of RCAN1, dependent on H2O2 stimulation. In addition, knockdown of beta-TrCP by siRNA abolished the H2O2-induced decrease in RCAN1 in HEK293T cells. We further examined whether RCAN1 undergoes ubiquitination by H2O2 in primary neurons, similarly to that in HEK293T cells. An H2O2-induced decrease in RCAN1 was exhibited also in hippocampal and cortical neurons. Ubiquitination of RCAN1 was induced by 500 muM H2O2, the concentration at which H2O2 induced a decrease in RCAN1 in primary neurons. These results suggest that H2O2 induces SCF beta-TrCP-mediated ubiquitination of RCAN1, leading to a decrease in the protein level of RCAN1.
Kishi Initiative Research Unit, Frontier Research System, 2-1 Hirosawa, Wako, Saitama, Japan.
Sachie
S
Asada
Akemi
A
Ikeda
Rina
R
Nagao
Hiroshi
H
Hama
Tatsuhiko
T
Sudo
Akiyoshi
A
Fukamizu
Yoshitoshi
Y
Kasuya
Tsutomu
T
Kishi
D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D051379:Mice; D009124:Muscle Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D018384:Oxidative Stress; D034741:RNA, Small Interfering / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D054875:Ubiquitination; D044844:beta-Transducin Repeat-Containing Proteins / Q000378:metabolism
C471644:BTRC protein, human; D004268:DNA-Binding Proteins; C471645:FBXW11 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins; C108612:RCAN1 protein, human; D034741:RNA, Small Interfering; D044844:beta-Transducin Repeat-Containing Proteins; D006861:Hydrogen Peroxide; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases