Nuclear cereblon modulates transcriptional activity of Ikaros and regulates its downstream target, enkephalin, in human neuroblastoma cells

Journal Article · Fri Aug 26 04:00:00 EDT 2016 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/J.BBRC.2016.06.091· OSTI ID:22606168

Wada, Takeyoshi ^[1]; Asahi, Toru ^[1]; Sawamura, Naoya ^[1]

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1. Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480 (Japan)

The gene coding cereblon (CRBN) was originally identified in genetic linkage analysis of mild autosomal recessive nonsyndromic intellectual disability. CRBN has broad localization in both the cytoplasm and nucleus. However, the significance of nuclear CRBN remains unknown. In the present study, we aimed to elucidate the role of CRBN in the nucleus. First, we generated a series of CRBN deletion mutants and determined the regions responsible for the nuclear localization. Only CRBN protein lacking the N-terminal region was localized outside of the nucleus, suggesting that the N-terminal region is important for its nuclear localization. CRBN was also identified as a thalidomide-binding protein and component of the cullin-4-containing E3 ubiquitin ligase complex. Thalidomide has been reported to be involved in the regulation of the transcription factor Ikaros by CRBN-mediated degradation. To investigate the nuclear functions of CRBN, we performed co-immunoprecipitation experiments and evaluated the binding of CRBN to Ikaros. As a result, we found that CRBN was associated with Ikaros protein, and the N-terminal region of CRBN was required for Ikaros binding. In luciferase reporter gene experiments, CRBN modulated transcriptional activity of Ikaros. Furthermore, we found that CRBN modulated Ikaros-mediated transcriptional repression of the proenkephalin gene by binding to its promoter region. These results suggest that CRBN binds to Ikaros via its N-terminal region and regulates transcriptional activities of Ikaros and its downstream target, enkephalin. - Highlights: • We found that CRBN is a nucleocytoplasmic shutting protein and identified the key domain for nucleocytoplasmic shuttling. • CRBN associates with the transcription factor Ikaros via the N-terminal domain. • CRBN modulates Ikaros-mediated transcriptional regulation and its downstream target, enkephalin.

• OSTI ID: 22606168
• Journal Information: Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 3 Vol. 477; ISSN BBRCA9; ISSN 0006-291X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
CYTOPLASM
ENKEPHALINS
GENES
LIGASES
LUCIFERASE
MUTANTS
PROMOTERS
RABBIT TUBES
TRANSCRIPTION
TRANSCRIPTION FACTORS