Figure 7.
Functional specificity is encoded by the N-terminal domain of hCdc20 and hCdh1. (A) Schematic showing the design of chimeric proteins exchanging the amino-termini and WD repeats of hCdc20 and hCdh1. (B) Ubiquitination assay using in vitro translated Cdh1, Cdc20, NCdh1–CCdc20, Cdc20N170, NCdc20–CCdh1, and Cdh1N173 to activate APC for ubiquitination of 35S-labeled cyc B-N. (C) Ubiquitination assay using Cdh1, Cdc20, NCdh1–CCdc20, and NCdc20–CCdh1 to activate APC for ubiquitination of 35S-labeled KEN-box containing Cdc20N170. An asterisk marks a background band present in the in vitro translation products in B and C. (D) Alignment of Cdch1 and Cdc20 family members from human (h), Xenopus (x), and Drosophila (Dm). Conserved residues of the DR(F/Y)IPXR are in bold type and are boxed.