title: Systematic biochemical characterization of the SAM domains in Eph receptor family from Mus Musculus.
abstract: The Eph receptor family is the largest subfamily of receptor tyrosine kinases and well-known for their pivotal roles in axon guidance, synaptogenesis, artery/venous differentiation and tumorigenesis, etc. Activation of the Eph receptor needs multimerization of the receptors. The intracellular C-terminal SAM domain of Eph receptor was reported to mediate self-association of Eph receptors via the homo SAM-SAM interaction. In this study, we systematically expressed and purified the SAM domain proteins of all fourteen Eph receptors of Mus musculus in Escherichia coli. The FPLC (fast protein liquid chromatography) results showed the recombinant SAM domains were highly homogeneous. Using CD (circular dichroism) spectrometry, we found that the secondary structure of all the SAM domains was typically alpha helical folded and remarkably similar. The thermo-stability tests showed that they were quite stable in solution. SEC-MALS (size exclusion chromatography coupled with multiple angle light scattering) results illustrated 200 μM Eph SAM domains behaved as good monomers in the size-exclusion chromatography. More importantly, DLS (dynamic light scattering) results revealed the overwhelming majority of SAM domains was not multimerized in solution either at 200 μM or 2000 μM protein concentration, which indicating the SAM domain alone was not sufficient to mediate the polymerization of Eph receptor. In summary, our studies provided the systematic biochemical characterizations of the Eph receptor SAM domains and implied their roles in Eph receptor mediated signaling pathways.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University, The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China.
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Li
authors.affiliation: Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University, The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China.
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China. Electronic address: ligang55@bjmu.edu.cn.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.affiliation: Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University, The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China; Division of Life Sciences, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China. Electronic address: liuw@ust.hk.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
mesh_terms: D000818:Animals; D001665:Binding Sites; D051379:Mice; D008970:Molecular Weight; D011485:Protein Binding; D036082:Receptor, EphA1 / Q000737:chemistry* / Q000648:ultrastructure*; D000071682:Sterile Alpha Motif; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D036082:Receptor, EphA1
keywords: Eph receptor; SAM domain