title: Crystal structure of hGEF-H1 PH domain provides insight into incapability in phosphoinositide binding.
abstract: The guanine nucleotide exchange factor GEF-H1 (also known as ARHGEF2) is identified as a member of the Dbl family of GEFs. It regulates RhoA-dependent cell signaling pathways and plays important roles in biological processes. GEF-H1 contains an N-terminal zinc finger domain, a Dbl-homologous (DH) domain followed by a Pleckstrin homology (PH) domain, and a C-terminal domain. The specific roles of its PH domain are poorly understood. Here we report the crystal structure of human GEF-H1 PH domain to 2.45 Å resolution. A conserved surface is formed by β8, β9, β10, and it may mediate protein-protein interactions. Although the folding resembles other PH domains that have defined structures, superposition of different PH domains clearly shows that the loop between β6/β7 and the loop between β3/β4 are so close that they will prevent its binding with phosphoinositide due to steric hindrance, and this has been proved by isothermal titration calorimetry (ITC) and thermal shift assay (TSA). Our studies provide a structural framework for further work on the function of GEF-H1.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Heli
authors.initials: H
authors.lastname: Jiang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Shaoyang
authors.initials: S
authors.lastname: Zhou
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Meng
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; iHuman Institute, Shanghai Tech University, Shanghai 201210, China. Electronic address: zjliu@ibp.ac.cn.
authors.forename: Zhi-Jie
authors.initials: ZJ
authors.lastname: Liu
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: ouyangsy@moon.ibp.ac.cn.
authors.forename: Songying
authors.initials: S
authors.lastname: Ouyang
mesh_terms: D000595:Amino Acid Sequence; D001798:Blood Proteins / Q000737:chemistry; D018360:Crystallography, X-Ray; D006801:Humans; D008969:Molecular Sequence Data; D010716:Phosphatidylinositols / Q000737:chemistry*; D010750:Phosphoproteins / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D064067:Rho Guanine Nucleotide Exchange Factors / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: C577356:ARHGEF2 protein, human; D001798:Blood Proteins; D010716:Phosphatidylinositols; D010750:Phosphoproteins; D064067:Rho Guanine Nucleotide Exchange Factors; C039077:platelet protein P47
keywords: Crystal structure; GEF-H1; PH domain; Phosphoinositide