Characterization of the Zn finger domain of the oncogenic protein MDM2

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12670079
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: General pharmacology
• Research Institution: Tohoku University
• Principal Investigator: SUKEGAWA Jun Tohoku Univ., Grad. Sch. Med., Dep. Mol. Pharmacol., Associate Professor, 大学院・医学系研究科, 助教授 (30187687)
• Co-Investigator(Kenkyū-buntansha): YANAGISAWA Teruyuki Tohoku Univ., Grad. Sch. Med., Dep. Mol. Pharmacol., Professor, 大学院・医学系研究科, 教授 (90133941)
• Project Period (FY): 2000 – 2001
• Keywords: GTP binding protein / Ran / MDM2 / Zn finger

Research Abstract

It has been considered that the Zn finger-like structure observed in Nup153, a component of mammalian nuclear pore complexes, would recognize and bind to some specific nucleotide sequence(s) as other common Zn finger proteins do. We have found, however, that the Zn finger-like structure binds specifically to one of the small GTP binding protein, Ran. The Zn finger-like structure of Nup153 consists of four repeats of an amino acid sequence containing regularly spacing cysteine residues. Because data base search showed several proteins possess one or two repeats of the Zn finger-like structure similar to that of Nup153, we asked if each repeat unit of the Nupl53 Zn finger-like structure is still capable of binding to Ran. Two-hybrid assay showed that peptides with two repeat units are capable of binding to Ran. However, single repeat units didn't show the activity. We asked next if MDM2, an oncogenic protein that contains a single unit of the Zn finger-like amino acid sequence, recognizes Ran. Although two-hybrid assay failed to show Ran-binding activity of MDM2, in vitro binding experiments indicated that MDM2 is indeed capable of binding to Ran. We are now pinpointing the Ran-binding sequence on MDM2.