Adamalysin (ADAM) function in cell signaling

Julia Zhong

Adamalysins (a disintegrin and metalloproteinase, ADAMs) are cell surface transmembrane proteins involved in cell adhesion, proteolytic processing or shedding of cell surface proteins. We demonstrated that the cytoplasmic domain of one member of the ADAM family, ADAM15, shows tyrosine phosphorylation-dependent interaction with components of the cell signalling machinery, including Src family protein tyrosine kinases (Lck and Hck) as well as the adaptor protein Grb2 in haematopoietic cell types (Jurkat, U937). We hypothesize that the cytoplasmic domain regulates ADAM activity, which could potentially contribute both to inside-out or outside-in cell signalling. The project involves analysis of the alternatively spliced ADAM15 variants and specific point or deletion mutants by characterization of existing interacting proteins, such as Hck, and identification of new interacting proteins. We are addressing the impact of manipulation of ADAM15 on cell adhesion, proliferation and motility, especially on PMA-induced differentiation of U937 to a macrophage like-adherent phenotype, using GST-pull-down/Western blotting co-mmunoprecipitation, immunocytochemistry and cell adhesion and migration assays.