New I-type lectins of the CD33-related siglec subgroup identified through genomics

Siglecs are sialic-acid-binding proteins of the Ig superfamily that are involved in cell-cell interactions and signalling. In recent years, several novel siglecs that are highly related to CD33/Siglec-2 have been identified through genomics and functional screens. In addition to their distinct sialic-acid-binding properties, most of these novel siglecs bear tyrosine-based signalling motifs that are typically found in inhibitory receptors of the immune system. The restricted expression patterns of CD33-related siglecs in the haemopoietic and immune systems suggests that they arc involved in regulating leucocyte activation during inflammatory and immune responses.