Predicted aa sequence of the FcγRIIc1-4 isoforms as compared with the previously described FcγRIIa1, b2, and c isoforms. Four representative FcγRIIc isoforms were identified and the translated sequence is shown in comparison to FcγRIIa1. The exon borders are demarcated by vertical lines and the numbering follows the aa position as previously described.20 The dashes represent sequence identity with the FcγRIIa1 isoform, the pluses represent deleted aa, and the stars indicate a stop codon. At positions 107, 120, and 161 unique changes in the aa sequence of FcγRIIc-specific isoforms are indicated. The ITAM within FcγRIIa and IIc sequences encompasses aa 254-272. The sequence data are available from GenBank under accesion numbers: U90938-U90941.