The Phospho-CXCR4 (Ser339) Fluorometric Cell-Based ELISA Kit provides a lysate-free, convenient, and high-throughput approach for monitoring Phospho-CXCR4 (Ser339) protein phosphorylation and expression profile in cells. The kit can be used for measuring the relative amounts of phosphorylated Phospho-CXCR4 (Ser339) in cultured cells as well as screening for the effects that various treatments, inhibitors (ie. siRNA or chemicals, or activators have on CAV1 phosphorylation.