Receptor for the C-X-C chemokine cxcl12/sdf-1. Transduces a signal by increasing the intracellular level of calcium ions. Signaling with cxcl12/sdf-1 mediates the directional movement of mesodermal cells during gastrulation. May play a role in the migration of embryonic presumptive primordial germ cells (pPGCs). May also be involved in regulating migration of hematopoietic stem cells into the larval liver (By similarity). Monomer. Can form dimers (By similarity). Expressed in the cytoplasm of a small number of embryonic pPGCs from stage 24. Expressed in the nucleus of 3 lateral pPGCs (By similarity). Sulfation is required for efficient binding of cxcl12/sdf-1alpha and promotes its dimerization. O- and N-glycosylated. Belongs to the G-protein coupled receptor 1 family.