Ubiquitination of Cyclin A by APC/C:Cdc20 complex

Stable Identifier
Reaction [transition]
Homo sapiens
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Rape et al. have recently demonstrated that the order in which APC/C targeted proteins are degraded is determined by the processivity of multiubiquitination of these substrates. Processive substrates acquire a polyubiquitin chain upon binding to the APC/C once and are degraded. Distributive substrates bind, dissociate and reassociate with the APC/C multiple times before acquiring an ubiquitin chain of sufficient length to insure degradation. In addition, distributive substrates that dissociate from the APC/C with short ubiquitin chains are targeted for deubiquitination (Rape et al., 2006). Paradoxically, although the multiubiquitination of cyclin A is distributive and later substrates of APC-Cdc20 such as Securin are processive (Rape et al., 2006), Cyclin A is degraded prior to Securin and Cyclin B. The mechanisms insuring this order have not yet be determined.
Literature References
PubMed ID Title Journal Year
11285280 Anaphase-promoting complex/cyclosome-dependent proteolysis of human cyclin A starts at the beginning of mitosis and is not subject to the spindle assembly checkpoint

Peters, JM, Gannon, J, Geley, S, Kramer, E, Gieffers, C, Hunt, T

J Cell Biol 2001
Event Information
Catalyst Activity

ubiquitin-protein transferase activity of MCC:APC/C complex [cytosol]

Orthologous Events
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