Structure of the anaphase-promoting complex/cyclosome interacting with a mitotic checkpoint complex.
Once all chromosomes are connected to the mitotic spindle (bioriented), anaphase is initiated by the protein ubiquitylation activity of the anaphase-promoting complex/cyclosome (APC/C) and its coactivator Cdc20 (APC/C(Cdc20)). Before chromosome biorientation, anaphase is delayed by a mitotic checkpoint complex (MCC) that inhibits APC/C(Cdc20). We used single-particle electron microscopy to obtain three-dimensional models of human APC/C in various functional states: bound to MCC, to Cdc20, or to neither (apo-APC/C). These experiments revealed that MCC associates with the Cdc20 binding site on APC/C, locks the otherwise flexible APC/C in a "closed" state, and prevents binding and ubiquitylation of a wide range of different APC/C substrates. These observations clarify the structural basis for the inhibition of APC/C by spindle checkpoint proteins.
Herzog
Franz
F
Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, 1030 Vienna, Austria.
Primorac
Ivana
I
Dube
Prakash
P
Lenart
Peter
P
Sander
Björn
B
Mechtler
Karl
K
Stark
Holger
H
Peters
Jan-Michael
JM
D000705:Anaphase; D064173:Anaphase-Promoting Complex-Cyclosome; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008854:Microscopy, Electron; D008938:Mitosis; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D008941:Spindle Apparatus / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000737:chemistry* / Q000378:metabolism*; D054875:Ubiquitination
D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; C577488:CDC20 protein, human; C105156:UBE2C protein, human; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome