Sheng Yi, Saridakis Vivian, Sarkari Feroz, Duan Shili, Wu Tianne, Arrowsmith Cheryl H, Frappier Lori
Ontario Cancer Institute, Department of Medical Biophysics, 101 College Street, Toronto, Ontario, Canada M5G 1L7.
Nat Struct Mol Biol. 2006 Mar;13(3):285-91. doi: 10.1038/nsmb1067. Epub 2006 Feb 12.
The ubiquitin-specific protease, USP7, has key roles in the p53 pathway whereby it stabilizes both p53 and MDM2. We show that the N-terminal domain of USP7 binds two closely spaced 4-residue sites in both p53 and MDM2, falling between p53 residues 359-367 and MDM2 residues 147-159. Cocrystal structures with USP7 were determined for both p53 peptides and for one MDM2 peptide. These peptides bind the same surface of USP7 as Epstein-Barr nuclear antigen-1, explaining the competitive nature of the interactions. The structures and mutagenesis data indicate a preference for a P/AXXS motif in peptides that bind USP7. Contacts made by serine are identical and crucial for all peptides, and Trp165 in the peptide-binding pocket of USP7 is also crucial. These results help to elucidate the mechanism of substrate recognition by USP7 and the regulation of the p53 pathway.
泛素特异性蛋白酶USP7在p53信号通路中发挥关键作用，它能使p53和MDM2均保持稳定。我们发现，USP7的N端结构域在p53和MDM2中均结合两个紧密相邻的4残基位点，分别位于p53的359 - 367位残基之间以及MDM2的147 - 159位残基之间。我们测定了p53肽段和一个MDM2肽段与USP7的共晶体结构。这些肽段与USP7结合的表面和爱泼斯坦 - 巴尔核抗原1相同，这解释了相互作用的竞争性。结构和诱变数据表明，结合USP7的肽段偏好P/AXXS基序。丝氨酸形成的接触对于所有肽段都是相同且至关重要的，USP7肽段结合口袋中的色氨酸165也至关重要。这些结果有助于阐明USP7识别底物的机制以及p53信号通路的调控机制。
