May have an regulatory role in normal and neoplastic B cell development.
Subcellular locations: Cell membrane
Expressed in the secondary lymphoid organs, spleen and lymph node. Expression is limited to the mature B-cell lines. Highly expressed in CD19 and within the mantle zones of the tonsil tissue. Isoform 2 is expressed in the spleen, peripheral blood and bone marrow. Isoform 2 and isoform 4 are expressed in B-cell lines. Preferentially expressed in memory B-cells (at protein level).