Sialic Acid Binding Ig Like Lectin 8 (SIGLEC8)

Floyd et al. (2000) identified a cDNA from an eosinophil cDNA library encoding SIGLEC8. Sequence analysis predicted that like other SIGLECs, the 431-amino acid, type 1 transmembrane protein contains a signal peptide, an N-terminal V-set domain, and 2 C2-set domains, as well as 3 potential N-linked glycosylation sites and a transmembrane region; however, SIGLEC8 has a truncated 47-residue cytoplasmic tail lacking the conserved tyrosine-based motifs.

Binding analysis confirmed that SIGLEC8 binds to red blood cell sialic acids with a preference for 3-prime over 6-prime sialyllactose-conjugated polyacrylamide. FACS and immunoprecipitation analyses demonstrated SIGLEC8 expression on eosinophils but not other leukocytes as a 45- and 89-kD dimer.