CXCR5 is a 55-60kD member of the G-protein coupled receptor 1 family.
It is expressed on select cell types, including granule and Purkinje cell neurons, embryonic CD4+ CD3- IL-7Ralpha+ precursor cells, B cells and follicular T helper cells.
CXCR5 selectively binds BLC/CXCL13.
This appears to both promote embryonic lymph node development and, in the adult, direct expressing cells to positions that optimize antigen presentation and antibody production.
Mouse CXCR5 is a 7-transmembrane glycoprotein that is 374 amino acids (aa) in length.
It contains a 57aa N-terminal extracellular region plus a 47aa C-terminal cytoplasmic domain.
Over aa1-57, mouse CXCR5 shares 84% and 47% aa identity with rat and human CXCR5, respectively.