| 背景信息 |
Sialic acid binding Ig like lectin 9 (SIGLEC9) is a transmembrane protein belonging to the immunoglobulin superfamily, characterized by an N-terminal Ig-like V-type domain responsible for sialic acid binding, followed by two Ig-like C2-type domains, a transmembrane region, and a cytoplasmic tail. The protein consists of 463 amino acids and is predominantly expressed on neutrophils, monocytes, a subset of NK cells, B cells, and some CD8+ T cells. SIGLEC9 mediates sialic acid-dependent cell adhesion, binding preferentially and equally to both α2,3- and α2,6-linked sialic acids, and is closely related to SIGLEC7, sharing about 80% sequence identity. Functionally, it is involved in cell-cell interactions and immune modulation through its carbohydrate-binding activity. Clinically, SIGLEC9 has been implicated in immune regulation and is associated with inflammatory and autoimmune diseases, as its expression and function can influence immune cell signaling and inflammatory responses. |