TPR subunits of the anaphase-promoting complex mediate binding to the activator protein CDH1
TPR subunits of the anaphase-promoting complex mediate binding to the activator protein CDH1
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DOI：
10.1016/s0960-9822(03)00581-5
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发表时间：
2003-09-02
期刊：
影响因子：
9.2
通讯作者：
Peters, JM
中科院分区：
文献类型：
--
作者：
Vodermaier, HC;Gieffers, C;Peters, JM
背景资料：染色体分离和有丝分裂退出依赖于由底物衔接蛋白CDC 20和CDH 1激活的后期促进复合物（APC）。APC是由至少11个亚基组成的泛素连接酶。APC 2和APC 11与E2酶的相互作用是足够的泛素化反应，但大多数其他亚基的功能是unknow.Results：我们有生化特征的亚复合物的人APC。一个亚复合物，含有APC 2/11，APC 1，APC 4和APC 5，可以组装多泛素链，但不能结合CDH 1和泛素化底物。另一个亚复合物包含除了APC 2/11之外的所有已知APC亚基。该亚复合物可以募集CDH 1，但不能支持任何泛素化反应。在体外，CDC 20和CDH 1的C末端与密切相关的TPR亚基APC 3和APC 7结合。同源建模预测，这些蛋白质在结构上类似于过氧化物酶体输入受体PEX 5，其通过其C末端结合货物蛋白。CDH 1激活APC依赖于一个保守的C-末端基序，该基序也存在于CDC 20和APC 10中。结论：APC 1、APC 4和APC 5可能与APC 2/11和TPR亚基连接。APC 3和APC 7中的TPR结构域将⑶ H 1募集到APC，从而可以使底物与APC 2/11和E2酶紧密接近。与PEX 5类似，APC的不同TPR亚基可能作为受体与调节蛋白如CDH 1、CDC 20和APC 10的C末端相互作用。
Background: Chromosome segregation and mitotic exit depend on activation of the anaphase-promoting complex (APC) by the substrate adaptor proteins CDC20 and CDH1. The APC is a ubiquitin ligase composed of at least 11 subunits. The interaction of APC2 and APC11 with E2 enzymes is sufficient for ubiquitination reactions, but the functions of most other subunits are unknown.Results: We have biochemically characterized subcomplexes of the human APC. One subcomplex, containing APC2/11, APC1, APC4, and APC5, can assemble multiubiquitin chains but is unable to bind CDH1 and to ubiquitinate substrates. The other subcomplex contains all known APC subunits except APC2/11. This subcomplex can recruit CDH1 but fails to support any ubiquitination reaction. In vitro, the C termini of CDC20 and CDH1 bind to the closely related TPR subunits APC3 and APC7. Homology modeling predicts that these proteins are similar in structure to the peroxisomal import receptor PEX5, which binds cargo proteins via their C termini. APC activation by CDH1 depends on a conserved C-terminal motif that is also found in CDC20 and APC10. Conclusions: APC1, APC4, and APC5 may connect APC2/11 with TPR subunits. TPR domains in APC3 and APC7 recruit CDH1 to the APC and may thereby bring substrates into close proximity of APC2/11 and E2 enzymes. In analogy to PEX5, the different TPR subunits of the APC might function as receptors that interact with the C termini of regulatory proteins such as CDH1, CDC20, and APC10.