Wnt-1 signal induces phosphorylation and degradation of c-Myb protein via TAK1, HIPK2, and NLK
- Chie Kanei-Ishii1,
- Jun Ninomiya-Tsuji3,
- Jun Tanikawa1,
- Teruaki Nomura1,
- Tohru Ishitani3,
- Satoshi Kishida3,
- Kenji Kokura1,
- Toshihiro Kurahashi1,2,
- Emi Ichikawa-Iwata1,
- Yongsok Kim4,
- Kunihiro Matsumoto3, and
- Shunsuke Ishii1,2,5
- 1Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, Tsukuba, Ibaraki 305-0074, Japan; 2University of Tsukuba, Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki 305-8577, Japan; 3Department of Molecular Biology, Graduate School of Science, Nagoya University, and CREST, Japan Science and Technology Corporation, Chikusa-ku, Nagoya 464-8602, Japan; 4Laboratory of Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
Abstract
The c-myb proto-oncogene product (c-Myb) regulates both the proliferation and apoptosis of hematopoietic cells by inducing the transcription of a group of target genes. However, the biologically relevant molecular mechanisms that regulate c-Myb activity remain unclear. Here we report that c-Myb protein is phosphorylated and degraded by Wnt-1 signal via the pathway involving TAK1 (TGF-β-activated kinase), HIPK2 (homeodomain-interacting protein kinase 2), and NLK (Nemo-like kinase). Wnt-1 signal causes the nuclear entry of TAK1, which then activates HIPK2 and the mitogen-activated protein (MAP) kinase-like kinase NLK. NLK binds directly to c-Myb together with HIPK2, which results in the phosphorylation of c-Myb at multiple sites, followed by its ubiquitination and proteasome-dependent degradation. Furthermore, overexpression of NLK in M1 cells abrogates the ability of c-Myb to maintain the undifferentiated state of these cells. The down-regulation of Myb by Wnt-1 signal may play an important role in a variety of developmental steps.
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Footnotes
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Supplemental material is available at http://www.genesdev.org.
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Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.1170604.
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Corresponding author.
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↵5 E-MAIL sishii{at}rtc.riken.jp; FAX 81-29-836-9030
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- Accepted March 1, 2004.
- Received November 19, 2003.
- Cold Spring Harbor Laboratory Press