The PathHunter eXpress BLK Activity Assay is a stable, engineered cell line for use in studying small molecule drug candidates targeting the BLK kinase domain. The cell line is engineered to express the catalytic domain from BLK fused to the cytokine receptor binding domain (CRBD) of JAK2. The cells co-express an Enzyme Acceptor (EA) tagged SH2 domain and a ProLink (PK) tagged Cytokine receptor. The CRBD is designed to bind the CTK catalytic domain to the GHR-PK. Activation of the GHR-PK induces receptor phosphorylation by the BLK catalytic domain. This leads to SH2-EA recruitment and production of EFC signal. eXpress kits are a convenient, ready-to-use format which contains all materials needed to run the assay, including single-use vials of cryopreserved cells, cell plating media, detection reagent, and assay plates. For detailed product information, User Manual and Datasheet, visit www.discoverx.com/express.