title: Localization of the coactivator Cdh1 and the cullin subunit Apc2 in a cryo-electron microscopy model of vertebrate APC/C.
abstract: The anaphase-promoting complex/cyclosome (APC/C) is a ubiquitin ligase with essential functions in mitosis, meiosis, and G1 phase of the cell cycle. APC/C recognizes substrates via coactivator proteins such as Cdh1, and bound substrates are ubiquitinated by E2 enzymes that interact with a hetero-dimer of the RING subunit Apc11 and the cullin Apc2. We have obtained three-dimensional (3D) models of human and Xenopus APC/C by angular reconstitution and random conical tilt (RCT) analyses of negatively stained cryo-electron microscopy (cryo-EM) preparations, have determined the masses of these particles by scanning transmission electron microscopy (STEM), and have mapped the locations of Cdh1 and Apc2. These proteins are located on the same side of the asymmetric APC/C, implying that this is where substrates are ubiquitinated. We have further identified a large flexible domain in APC/C that adopts a different orientation upon Cdh1 binding. Cdh1 may thus activate APC/C both by recruiting substrates and by inducing conformational changes.
authors.affiliation: Max-Planck-Institute for Biophysical Chemistry, Goettingen, Germany.
authors.forename: Prakash
authors.initials: P
authors.lastname: Dube
authors.forename: Franz
authors.initials: F
authors.lastname: Herzog
authors.forename: Christian
authors.initials: C
authors.lastname: Gieffers
authors.forename: Bjoern
authors.initials: B
authors.lastname: Sander
authors.forename: Dietmar
authors.initials: D
authors.lastname: Riedel
authors.forename: Shirley A
authors.initials: SA
authors.lastname: Müller
authors.forename: Andreas
authors.initials: A
authors.lastname: Engel
authors.forename: Jan-Michael
authors.initials: JM
authors.lastname: Peters
authors.forename: Holger
authors.initials: H
authors.lastname: Stark
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D064198:Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome; D020285:Cryoelectron Microscopy; D044842:Cullin Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008958:Models, Molecular; D008970:Molecular Weight; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D044842:Cullin Proteins; D021122:Protein Subunits; D025801:Ubiquitin; D043743:Ubiquitin-Protein Ligase Complexes; C577351:ANAPC11 protein, human; D064173:Anaphase-Promoting Complex-Cyclosome; D064198:Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases