sialoadhesins
Sialoadhesins are a subfamily of immunoglobulin superfamily members that function as sialic acid–binding lectins on leukocyte surfaces. The family includes proteins such as CD33 (Siglec-3), CD169 (Siglec-1), CD172a (Siglec-5), and CD169e (Siglec-7). Each sialoadhesin contains an extracellular domain composed of an N‑terminal V-set immunoglobulin domain followed by multiple C2‑type Ig-like domains, a transmembrane segment, and a short cytoplasmic tail that may contain immunoreceptor‑tyrosine–based inhibitory motifs (ITIMs). The N‑terminal domain confers specificity for α2,3‑ or α2,6‑linked sialic acids on glycoproteins and glycolipids.
Sialoadhesins are expressed predominantly on myeloid cells, including macrophages, microglia, and dendritic cells, and play roles
The nomenclature of sialoadhesins follows the Siglec (sialic acid–binding immunoglobulin-like lectin) classification. Structural studies have revealed