2014 年 3 巻 2 号 p. 199-203
Siglecs are a family of vertebrate glycan-recognition proteins belonging to the immunoglobulin superfamily, which recognize oligosaccharides containing acidic sugars called sialic acid. Most Siglecs are primarily expressed on leukocytes, and have crucial roles in regulating the viability and activity of the cells that express them. While most Siglecs associate with tyrosine phosphatases and negatively regulate immune cells, a small subset of Siglecs associate with an adapter molecule and recruit tyrosine kinase, triggering a signaling cascade leading to the activation of immune cells. Recent studies revealed that activating-type Siglecs are involved in various aspects of biology, such as defense against pathogens, bone homeostasis, and possibly cancer. Genetic polymorphisms of activating-type Siglecs might be associated with modern diseases caused by changes in human lifestyle and our extended lifespan, and deserve investigation from various angles.