Activation of the anaphase-promoting complex/cyclosome (APC/C) by Cdc20 and Cdh1 leads to ubiquitin-dependent degradation of securin and cyclin B and thereby promotes the initiation of anaphase and exit from mitosis. Cyclin B and securin ubiquitination depend on a destruction box (D box) sequence in these proteins, but how APC/C bound to Cdc20 or Cdh1 recognizes the D box is poorly understood. By using site-specific photocrosslinking in combination with mutational analyses, we show that the D box directly interacts with an evolutionarily conserved surface on the predicted WD40 propeller structure of Cdh1 and that this interaction is essential for processive substrate ubiquitination. We further show that Cdh1 specifically crosslinks to the APC/C subunit Cdc27 and that Cdh1 binding to APC/C depends on the presence of Cdc27. Our data imply that APC/C is activated by the association of Cdh1 with Cdc27, which enables APC/C to recognize the D box of substrates via Cdh1's propeller domain.
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http://dx.doi.org/10.1016/j.molcel.2005.04.023 | DOI Listing |
Heliyon
October 2024
Department of Endocrinology, the Third Xiangya Hospital, Central South University, Changsha, China.
G3 (Bethesda)
October 2024
Department of Plant Sciences, North Dakota State University, Fargo, ND, USA 58108.
Flavonoids are secondary metabolites associated with plant seed coat and flower color. These compounds provide health benefits to humans as anti-inflammatory and antioxidant compounds. The expression of the late biosynthetic genes in the flavonoid pathway is controlled by a ternary MBW protein complex consisting of interfacing MYB, beta-helix-loop-helix (bHLH), and WD40 Repeat (WDR) proteins.
View Article and Find Full Text PDFOpen Biol
June 2024
Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
Faithful transmission of genetic material is crucial for the survival of all organisms. In many eukaryotes, a feedback control mechanism called the spindle checkpoint ensures chromosome segregation fidelity by delaying cell cycle progression until all chromosomes achieve proper attachment to the mitotic spindle. Kinetochores are the macromolecular complexes that act as the interface between chromosomes and spindle microtubules.
View Article and Find Full Text PDFNat Commun
November 2023
Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Shenzhen, 518172, China.
AMBRA1 is a tumor suppressor protein that functions as a substrate receptor of the ubiquitin conjugation system with roles in autophagy and the cell cycle regulatory network. The intrinsic disorder of AMBRA1 has thus far precluded its structural determination. To solve this problem, we analyzed the dynamics of AMBRA1 using hydrogen deuterium exchange mass spectrometry (HDX-MS).
View Article and Find Full Text PDFJ Mol Endocrinol
July 2023
Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
WD40 repeat-containing proteins play a key role in many cellular functions including signal transduction, protein degradation, and apoptosis. The WD40 domain is highly conserved, and its typical structure is a β-propeller consisting of 4-8 blades which probably serves as a scaffold for protein-protein interaction. Some WD40 repeat-containing proteins form part of the corepressor complex of nuclear hormone receptors, a family of ligand-dependent transcription factors that play a central role in the regulation of gene transcription.
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