Ubiquitination of Cyclin A by APC/C:Cdc20 complex Authored: Lorca, T, Castro, A, 2006-01-26 00:00:00 EC Number: 6.3.2.19 Edited: Matthews, L, 2006-02-17 05:46:22 GENE ONTOLOGYGO:0042787 Pubmed11285280 Pubmed16413484 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. Reactome Database ID Release 43174104 Reactome, http://www.reactome.org ReactomeREACT_6824 Reviewed: Peters, JM, 2006-03-27 22:55:09 has a Stoichiometric coefficient of 4 ubiquitin multiubiquitinated Cyclin A associated with MCC:APC/C complex Cdc2:Cyclin A:MCC:APC/C complex