Figure 2: Signaling pathways downstream CXCR4 receptor activation. Upon CXCL12 binding the G protein complex dissociates into 𝛼 and 𝛽 𝛾 subunits that trigger parallel signal transduction cascades culminating in tumor cell proliferation, migration, or survival. AC: adenylyl cyclase; ER: endoplasmic reticulum; PLC: phospholipase C; PI3K: phosphoinositide 3-kinase; PKB/Akt: protein kinase B; PKC: protein kinase C; PYK2: proline-rich tyrosine kinase 2; ERK1/2: extracellular regulated kinase.