title: EphrinB1 interacts with the transcriptional co-repressor Groucho/xTLE4.
abstract: Ephrin signaling is involved in various morphogenetic events, such as axon guidance, hindbrain segmentation, and angiogenesis. We conducted a yeast two-hybrid screen using the intracellular domain (ICD) of EphrinB1 to gain biochemical insightinto the function of the EphrinB1 ICD. We identified the transcriptional co-repressor xTLE1/Groucho as an EphrinB1 interacting protein. Whole-mount in situ hybridization of Xenopus embryos confirmed the co-localization of EphrinB1 and a Xenopus counterpart to TLE1, xTLE4, during various stages of development. The EphrinB1/xTLE4 interaction was confirmed by co-immunoprecipitation experiments. Further characterization of the interaction revealed that the carboxy-terminal PDZ binding motif of EphrinB1 and the SP domain of xTLE4 are required for binding. Additionally, phosphorylation of EphrinB1 by a constitutively activated fibroblast growth factor receptor resulted in loss of the interaction, suggesting that the interaction is modulated by tyrosine phosphorylation of the EphrinB1 ICD.
authors.affiliation: Laboratory of Cell and Developmental Signaling, National Cancer Institute-Frederick, Maryland 21702, USA.
authors.forename: Teddy
authors.initials: T
authors.lastname: Kamata
authors.forename: Yong-Sik
authors.initials: YS
authors.lastname: Bong
authors.forename: Kathleen
authors.initials: K
authors.lastname: Mood
authors.forename: Mae Ja
authors.initials: MJ
authors.lastname: Park
authors.forename: Tagvor G
authors.initials: TG
authors.lastname: Nishanian
authors.forename: Hyun-Shik
authors.initials: HS
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D056970:Co-Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D036387:Ephrin-B1 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D020798:Two-Hybrid System Techniques; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000033:anatomy & histology / Q000196:embryology / Q000235:genetics / Q000378:metabolism
chemical_list: D056970:Co-Repressor Proteins; D036387:Ephrin-B1; D012097:Repressor Proteins; C499043:TLE1 protein, human; C523700:TLE4 protein, Xenopus; D029867:Xenopus Proteins