title: Rapid characterization of the binding property of HtrA2/Omi PDZ domain by validation screening of PDZ ligand library.
abstract: HtrA2/Omi is a mammalian mitochondrial serine protease, and was found to have dual roles in mammalian cells, not only acting as an apoptosis-inducing protein but also maintaining mitochondrial homeostasis. PDZ domain is one of the most important protein-protein interaction modules and is involved in a variety of important cellular functions, such as signal transduction, degradation of proteins, and formation of cytoskeleton. Recently, it was reported that the PDZ domain of HtrA2/Omi might regulate proteolytic activity through its interactions with ligand proteins. In this study, we rapidly characterized the binding properties of HtrA2/Omi PDZ domain by validation screening of the PDZ ligand library with yeast two-hybrid approach. Then, we predicted its novel ligand proteins in human proteome and reconfirmed them in the yeast two-hybrid system. Finally, we analyzed the smallest networks bordered by the shortest path length between the protein pairs of novel interactions to evaluate the confidence of the identified interactions. The results revealed some novel binding properties of HtrA2/Omi PDZ domain. Besides the reported Class II PDZ motif, it also binds to Class I and Class III motifs, and exhibits restricted variability at P(-3), which means that the P(-3) residue is selected according to the composition of the last three residues. Seven novel ligand proteins of HtrA2/Omi PDZ domain were discovered, providing significant clues for further clarifying the roles of HtrA2/Omi. Moreover, this study proves the high efficiency and practicability of the newly developed validation screening of candidate ligand library method for binding property characterization of peptide-binding domains.
authors.affiliation: Proteomics Research Center, National Key Laboratory of Medical Molecular Biology, Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences / Peking Union Medical College, Beijing, 100005, China.
authors.forename: SuCan
authors.initials: S
authors.lastname: Ma
authors.forename: Eli
authors.initials: E
authors.lastname: Song
authors.forename: ShiJuan
authors.initials: S
authors.lastname: Gao
authors.forename: Rui
authors.initials: R
authors.lastname: Tian
authors.forename: YouHe
authors.initials: Y
authors.lastname: Gao
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D001854:Bone Marrow Cells / Q000502:physiology; D019295:Computational Biology; D016384:Consensus Sequence; D018076:DNA, Complementary; D015723:Gene Library; D006801:Humans; D008024:Ligands; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D008024:Ligands; D012697:Serine Endopeptidases