YFP-CXCR4 localization in response to SDF-1. (A) YFP-CXCR4 expression on the surfaces of MM.1S cells in unstimulated cells as determined by the fixed cell method. (B) Internalization of the CXCR4 receptor in response to SDF-1 (30 nM) stimulation for 1 hour. (C) Live cell method with 3D reconstruction demonstrating CXCR4 cytoskeletal rearrangement, capping, and pseudopodia formation in response to SDF-1.