ENDOSOMAL TARGETING BY THE CYTOPLASMIC TAIL OF MEMBRANE IMMUNOGLOBULIN

Membrane-bound immunoglobulin (mlg) of the IgG, IgA, and IgE classes h ave conserved cytoplasmic tails. To investigate the function of these tails, a B cell line was transfected with truncated or mutated gamma 2 a heavy chains. Transport to the endosomal compartment of antigen boun d by the B cell antigen receptor did not occur in the absence of the c ytoplasmic tail; and one or two mutations, respectively, in the Tyr-X- X-Met motif of the tail partially or completely interrupted the proces s. Experiments with chimeric antigen receptors confirmed these finding s. Thus, a role for the cytoplasmic tail of mlg heavy chains in endoso mal targeting of antigen is revealed.