Sialic acid-binding immunoglobulin-like lectin 5 (SIGLEC5)

Sialic acid-binding immunoglobulin-like lectin 5 (SIGLEC5), also known as CD170, is a cell surface inhibitory receptor highly expressed on myeloid cells such as monocytes, macrophages, and neutrophils[1][4][5]. It belongs to the CD33-related subset of the Siglec family, which are type I transmembrane proteins in the immunoglobulin superfamily that recognize sialic acid-containing glycans through a V-set Ig-like domain[2][3]. Upon ligand binding, SIGLEC5 transduces inhibitory signals through intracellular immunoreceptor tyrosine-based inhibitory motifs (ITIMs), recruiting protein tyrosine phosphatases (SHP-1/SHP-2) that downmodulate immune cell activation and inflammatory responses[2][5][7]. SIGLEC5 participates in immune evasion by pathogens such as Group B Streptococcus and is implicated in the regulation of innate and adaptive immunity, playing possible roles in infection, inflammation, and cancer biology[1][2][5].

Other names

CD170CD33 antigen-like 2OBBP2OB-BP2SIGLEC-5Obesity-binding protein 2

Modulation of immune cell signaling via sialic acid-dependent binding; Inhibits activation of monocytes, macrophages, and neutrophils via ITIM motifs recruiting SHP-1/SHP-2 phosphatases[2][7]