The B-cell receptor includes both CD79 and the immunoglobulin. The plasma membrane of a B cell is indicated by the green phospholipids. The B cell receptor extends both outside the cell (above the plasma membrane) and inside the cell (below the membrane).The B-cell receptor or BCR is a transmembrane receptor protein located on the outer surface of B-cells.he plasma membrane of a B cell is indicated by the green phospholipids. The B cell receptor extends both outside the cell (above the plasma membrane) and inside the cell (below the membrane). The B-cell receptor or BCR is a transmembrane receptor protein located on the outer surface of B-cells.