title: Hydrophilic residues are crucial for ribosomal protein L11 (RPL11) interaction with zinc finger domain of MDM2 and p53 protein activation.
abstract: Ribosomal protein L11 (RPL11) has been shown to activate p53 by binding to MDM2 and negating its p53 suppression activity in response to ribosomal stress. Although a mutation at Cys-305 within the zinc finger domain of MDM2 has been shown to drastically impair MDM2 interaction with RPL11 and thus escapes the inhibition by this ribosomal protein, it still remains elusive whether RPL11 inactivates MDM2 via direct action on this zinc finger domain and what is the chemical nature of this specific interaction. To define the roles of the MDM2 zinc finger in association with RPL11, we conducted hydrogen-deuterium exchange mass spectrometry, computational modeling, circular dichroism, and mutational analyses of the zinc finger domain of MDM2 and human RPL11. Our study reveals that RPL11 forms a stable complex with MDM2 in vitro through direct contact with its zinc finger. This binding is disrupted by single mutations of non-cysteine amino acids within the zinc finger domain of MDM2. Basic residues in RPL11 are crucial for the stable binding and RPL11 suppression of MDM2 activity toward p53. These results provide the first line of evidence for the specific interaction between RPL11 and the zinc finger of MDM2 via hydrophilic residues as well as a molecular foundation for better understanding RPL11 inhibition of MDM2 function.
authors: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-Simon Cancer Center, Indianapolis, Indiana 46032.
authors: Qi
authors: Q
authors: Zhang
authors: Department of Pathology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461.
authors: Hui
authors: H
authors: Xiao
authors: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-Simon Cancer Center, Indianapolis, Indiana 46032.
authors: Sergio C
authors: SC
authors: Chai
authors: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-Simon Cancer Center, Indianapolis, Indiana 46032.
authors: Quyen Q
authors: QQ
authors: Hoang
authors: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-Simon Cancer Center, Indianapolis, Indiana 46032. Electronic address: hualu@iupui.edu.
authors: Hua
authors: H
authors: Lu
mesh_terms: D000595:Amino Acid Sequence; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D013058:Mass Spectrometry / Q000379:methods; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011485:Protein Binding; D025941:Protein Interaction Mapping; D051736:Proto-Oncogene Proteins c-mdm2 / Q000737:chemistry*; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D016335:Zinc Fingers
chemical_list: D012269:Ribosomal Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C027624:ribosomal protein L11; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D005982:Glutathione Transferase