Identification of phosphotyrosine binding domain-containing proteins as novel downstream targets of the EphA8 signaling function.
Eph receptors and ephrins have been implicated in a variety of cellular processes, including morphology and motility, because of their ability to modulate intricate signaling networks. Here we show that the phosphotyrosine binding (PTB) domain-containing proteins AIDA-1b and Odin are tightly associated with the EphA8 receptor in response to ligand stimulation. Both AIDA-1b and Odin belong to the ankyrin repeat and sterile alpha motif domain-containing (Anks) protein family. The PTB domain of Anks family proteins is crucial for their association with the juxtamembrane domain of EphA8, whereas EphA8 tyrosine kinase activity is not required for this protein-protein interaction. In addition, we found that Odin is a more physiologically relevant partner of EphA8 in mammalian cells. Interestingly, overexpression of the Odin PTB domain alone attenuated EphA8-mediated inhibition of cell migration in HEK293 cells, suggesting that it acts as a dominant-negative mutant of the endogenous Odin protein. More importantly, small interfering RNA-mediated Odin silencing significantly diminished ephrinA5-induced EphA8 signaling effects, which inhibit cell migration in HEK293 cells and retract growing neurites of Neuro2a cells. Taken together, our findings support a possible function for Anks family proteins as scaffolding proteins of the EphA8 signaling pathway.
Shin
Jongdae
J
Department of Biological Science, Sookmyung Women's University, Chungpa-Dong 2-Ka, Yongsan-Ku, Seoul 140-742, South Korea.
Gu
Changkyu
C
Park
Eunjeong
E
Park
Soochul
S
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D036386:Ephrin-A5 / Q000494:pharmacology; D005333:Fetus / Q000187:drug effects / Q000378:metabolism; D015723:Gene Library; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D051379:Mice; D016501:Neurites / Q000187:drug effects / Q000201:enzymology; D019000:Phosphotyrosine / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D036143:Receptor, EphA8 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D020798:Two-Hybrid System Techniques
C489945:ANKS1B protein, human; D002352:Carrier Proteins; D036386:Ephrin-A5; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D019000:Phosphotyrosine; D036143:Receptor, EphA8