The Role Of C-Abl Kinase And Vav1in Mediating Neutrophil Migration

The inflammatory response is a multi-step process. The leukocyte activated fromthe blood into the surrounding tissue of the infection site depends on the inflammatoryfactors and chemoattractants. Neutrophil is one of the most important leukocyte in thehuman and neutrophil migration is particularly important in eradicating the invadingpathogens for the acute inflammation. c-Abl kinase is a non-receptor tyrosine kinase.that is able to activate many protein signaling molecules which participate in celldifferentiation, aging, apoptosis, and cell migration. Being an important signalingmolecule in cell, Vav1is an guanine nucleotide exchange factor that can activateRhoGTP proteins(Rho, RhoG, Rac, andCdc42) by converting the RhoGDP-boundinactive form into its GTP-binding activated form. It plays very important role inregulating T-cell growth and development, as well as activating mature T-cell andTCR signal transduction.Similarly, Vav1can regulate cytoskeletal morphology.In this thesis，we used three dimensional Agarose hanging drops and Transwellexperiments to show that when c-Abl kinase suppressed，neutrophil migration issignificantly affected. This indicates that c-Abl kinase is crucial for neutrophilmigration. The preliminary results of our laboratory show that the c-Abl kinase caninteract with Vav1. Through co-immunoprecipitation experiments,we can see c-Ablkinase and Vav1exist in the same protein complex.In order to study the interactionbetween c-Abl kinase and Vav1, We constructed different truncation protein domainsof Vav1. From GST-pull down assay, we can see Vav1can directly associates withc-Abl kinase through its C-terminal SH3-SH2-SH3domain and proline rich region isthe key structural-domain that mediates its interaction with the c-Abl kinase.Theresults of our study laid a foundation to further explore the dynamic mechanisms ofneutrophil migration.