Uniform TitleRegulation of process retraction and cell migration by Epha3 is mediated by the by the adaptor protein Nck1
NameHu, Tianjing (author), Zhou, Renping (chair), Wagner, George (internal member), Hsu, Shu (internal member), Minden, Audrey (outside member), Rutgers University, Graduate School - New Brunswick,
Central nervous system,
DescriptionMembers of the largest RTK (receptor tyrosine kinase) family, Eph receptors, and their ligands play pivotal roles in embryonic development. They have been shown to regulate axon guidance, cell migration, tissue boundary formation, synaptogenesis, and angiogenesis. In addition, mis-regulation of the Eph receptor function leads to tumorigenesis and possibly other diseases. However, little is known about signaling pathways downstream of Eph receptors. To shed light on signaling mechanisms of Eph receptors, we conducted a large-scale yeast two-hybrid screen to identify protein that interact with EphA receptors. In this screen, many promising candidates were identified, several of which warrant future investigation. A SH2/SH3 adaptor protein, Nck1, stands out as the strongest interactor with both EphA3 and EphA5. To better understand the signaling mechanisms of the EphAs and the role of Nck1, we performed in-depth studies on fibroblast cells and primary neurons. Here we present evidence that Nck1 interacts directly with activated EphA3 receptor through its SH2 domain and the juxtamembrane domain tyrosine residue 602 on EphA3. We find that the disruption of Nck1 binding by either SH2 domain or SH3 domains negatively regulates EphA3-mediated signaling during cell migration and cell process extension in HEK293A cells. Intriguingly, we also find that expression of Nck1 mutants through adenoviruses is not able to prevent growth cone collapse in primary hippocampal explants. These observations suggest that Nck1 plays a key role in mediating some aspects of EphA receptor functions.
Key words: Eph, ephrin, Receptor tyrosine kinase, SH2 domain, Nck1, Yeast two-hybrid, Hippocampal neuron culture.
NoteIncludes bibliographical references (p. 176-197).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.