E-type cyclins (E1 and E2) regulate the S phase program in the mammalian cell division cycle. Expression of cyclin E1 and E2 is frequently deregulated in a variety of cancer types and a wealth of experimental evidence supports an oncogenic role of these proteins in human tumorigenesis. Although the molecular mechanisms responsible for cyclin E1 deregulation in cancer are well defined, little is known regarding cyclin E2. Here we report that cyclin E2 is targeted for ubiquitin-dependent proteolysis by the ubiquitin ligase SCF(Fbxw7/hCdc4). Ubiquitylation is triggered by phosphorylation of cyclin E2 on residues Thr392 and Ser396, and to a lesser extent Thr74, contained in two consensus Cdc4-phosphodegrons. Furthermore, we found that ectopic expression of cyclin E1 enhances the ubiquitin-dependent proteolysis of cyclin E2 in vivo, suggesting a potential cross-talk in the regulation of E-type cyclin activity. Since SCF(Fbxw7/hCdc4) is functionally inactivated in several human cancer types, alteration of this molecular pathway could contribute to the deregulation of cyclin E2 in tumorigenesis.
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http://dx.doi.org/10.1016/j.yexcr.2008.11.017 | DOI Listing |
J Transl Med
January 2025
Cancer Institute, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China.
Background: The sustained activation of androgen receptor splice variant-7 (AR-V7) is a key factor in the resistance of castration-resistant prostate cancer (CRPC) to second-generation anti-androgens such as enzalutamide (ENZ). The AR/AR-V7 protein is regulated by the E3 ubiquitin ligase STUB1 and a complex involving HSP70, but the precise mechanism remains unclear.
Methods: High-throughput RNA sequencing was used to identify differentially expressed circular RNAs (circRNAs) in ENZ-resistant and control CRPC cells.
bioRxiv
January 2025
Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan.
DNA-damaging agents (DDAs) have long been used in cancer therapy. However, the precise mechanisms by which DDAs induce cell death are not fully understood and drug resistance remains a major clinical challenge. Schlafen 11 (SLFN11) was identified as the gene most strongly correlated with the sensitivity to DDAs based on mRNA expression levels.
View Article and Find Full Text PDFCell Biol Toxicol
January 2025
Department of General Surgery, Shengjing Hospital of China Medical University, 36 Sanhao Street, 110004, Shenyang, China.
Background: RING finger protein 112 (RNF112) exerts a key role in human tumors. However, its biological function in colorectal cancer (CRC) has not been discussed. We aimed to explore the function and molecular mechanism of RNF112 in CRC.
View Article and Find Full Text PDFJ Med Chem
January 2025
Institute of Pharmaceutical Chemistry, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany.
Members of the casein kinase 1 (CK1) family have emerged as key regulators of cellular signaling and as potential drug targets. Functional annotation of the 7 human isoforms would benefit from isoform-selective inhibitors, allowing studies on the role of these enzymes in normal physiology and disease pathogenesis. However, due to significant sequence homology within the catalytic domain, isoform selectivity is difficult to achieve with conventional small molecules.
View Article and Find Full Text PDFCell Rep
December 2024
School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093, USA. Electronic address:
Translation control mechanisms connect the largely static genome to the highly dynamic proteome. At each step in the translation cycle, multiple layers of regulation enable efficient protein biogenesis under optimal conditions and mediate responses to acute environmental challenges. Recent research has demonstrated that individual ribosomal protein ubiquitylation events act as molecular signals to specify quality control pathway outcomes.
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