Kanae Yumimoto

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In the mammalian circadian clockwork, CRY1 and CRY2 repressor proteins are regulated by posttranslational modifications for temporally coordinated transcription of clock genes. Previous studies revealed that FBXL3, an F-box-type E3 ligase, ubiquitinates CRYs and mediates their degradation. Here, we found that FBXL21 also ubiquitinates CRYs but counteracts(More)
Although elucidation of enzyme-substrate relations is fundamental to the advancement of biology, universal approaches to the identification of substrates for a given enzyme have not been established. It is especially difficult to identify substrates for ubiquitin ligases, given that most such substrates are immediately ubiquitylated and degraded as a result(More)
From the Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan; CREST, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan; and the Department of Biochemistry, Institute of Biomedical and Health Sciences, University of(More)
How stem cells maintain their stemness or initiate exit from the stem cell state for differentiation remains largely unknown. Aldehyde dehydrogenase (ALDH) activity is a hallmark of stem cells-including embryonic, adult tissue, and cancer stem cells-and is essential for their maintenance. The mechanisms by which ALDH activity is regulated in stem cells have(More)
Induced pluripotent stem cells (iPSCs) share many biological properties with embryonic stem cells (ESCs), and are generated from somatic cells by expression of some transcription factors such as Oct3/4, Sox2, Klf4 and c-Myc. Among these factors, the abundance of c-Myc is strictly regulated by Fbxw7, a subunit of Skp1-Cul1-F-box protein-type ubiquitin(More)
Although identification of substrates for ubiquitin ligase (E3) is important for understanding its biological functions, detection of the interaction between an E3 and its substrates has remained challenging. We recently developed a new approach, termed differential proteomics-based identification of ubiquitylation substrates (DiPIUS), for the discovery of(More)
A GATA family transcription factor, GATA-binding protein 2 (GATA2), participates in cell growth and differentiation of various cells, such as hematopoietic stem cells. Although its expression level is controlled by transcriptional induction and proteolytic degradation, the responsible E3 ligase has not been identified. Here, we demonstrate that F-box/WD(More)
The gene encoding F-box protein FBXW7 is frequently mutated in many human cancers. Although most previous studies have focused on the tumor-suppressive capacity of FBXW7 in tumor cells themselves, we determined that FBXW7 in the host microenvironment also suppresses cancer metastasis. Deletion of Fbxw7 in murine BM-derived stromal cells induced accumulation(More)
MDM2 mediates the ubiquitylation and thereby triggers the proteasomal degradation of the tumor suppressor protein p53. However, genetic evidence suggests that MDM2 contributes to multiple regulatory networks independently of p53 degradation. We have now identified the DEAD-box RNA helicase DDX24 as a nucleolar protein that interacts with MDM2. DDX24 was(More)