title: Structural basis for the subunit assembly of the anaphase-promoting complex.
abstract: The anaphase-promoting complex or cyclosome (APC/C) is an unusually large E3 ubiquitin ligase responsible for regulating defined cell cycle transitions. Information on how its 13 constituent proteins are assembled, and how they interact with co-activators, substrates and regulatory proteins is limited. Here, we describe a recombinant expression system that allows the reconstitution of holo APC/C and its sub-complexes that, when combined with electron microscopy, mass spectrometry and docking of crystallographic and homology-derived coordinates, provides a precise definition of the organization and structure of all essential APC/C subunits, resulting in a pseudo-atomic model for 70% of the APC/C. A lattice-like appearance of the APC/C is generated by multiple repeat motifs of most APC/C subunits. Three conserved tetratricopeptide repeat (TPR) subunits (Cdc16, Cdc23 and Cdc27) share related superhelical homo-dimeric architectures that assemble to generate a quasi-symmetrical structure. Our structure explains how this TPR sub-complex, together with additional scaffolding subunits (Apc1, Apc4 and Apc5), coordinate the juxtaposition of the catalytic and substrate recognition module (Apc2, Apc11 and Apc10 (also known as Doc1)), and TPR-phosphorylation sites, relative to co-activator, regulatory proteins and substrates.
authors.affiliation: Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Schreiber
authors.forename: Florian
authors.initials: F
authors.lastname: Stengel
authors.forename: Ziguo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Radoslav I
authors.initials: RI
authors.lastname: Enchev
authors.forename: Eric H
authors.initials: EH
authors.lastname: Kong
authors.forename: Edward P
authors.initials: EP
authors.lastname: Morris
authors.forename: Carol V
authors.initials: CV
authors.lastname: Robinson
authors.forename: Paula C A
authors.initials: PC
authors.lastname: da Fonseca
authors.forename: David
authors.initials: D
authors.lastname: Barford
mesh_terms: D020816:Amino Acid Motifs; D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D064190:Apc2 Subunit, Anaphase-Promoting Complex-Cyclosome; D064193:Apc5 Subunit, Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D055162:Biocatalysis; D002460:Cell Line; D020035:Holoenzymes / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D013058:Mass Spectrometry; D008854:Microscopy, Electron; D008958:Models, Molecular; D008970:Molecular Weight; D011485:Protein Binding; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure; D012542:Scattering, Radiation; D012568:Schizosaccharomyces / Q000737:chemistry; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D043743:Ubiquitin-Protein Ligase Complexes / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D054875:Ubiquitination
chemical_list: C577378:APC5 protein, S cerevisiae; D064193:Apc5 Subunit, Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577441:CDC23 protein, S cerevisiae; D020035:Holoenzymes; D021122:Protein Subunits; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; C577346:APC2 protein, S cerevisiae; D064173:Anaphase-Promoting Complex-Cyclosome; D064190:Apc2 Subunit, Anaphase-Promoting Complex-Cyclosome