Fig. 1. Sequence of AE1/F_c receptor chimeras. The sequence of the AE1/F_c receptor chimeras is illustrated. The putative boundary between the cytoplasmic domain and the transmembrane domain of these proteins is shown. The numbering at the top refers to the amino-acid sequence at the N-terminus of AE1-4. The sequences within amino acids 1-63 of AE1-4 that are homologous to known sorting signals are underlined. Residues within this region of AE1-4 that are identical to amino acids in the poly Ig receptor sorting signal are marked with a plus. The spacing between the arginine and serine in this poly Ig-like sorting signal is the same as that in the poly Ig receptor. The asterisk at the end of each sequence corresponds to a stop codon.