CLEC9A, also known as DNGR1, is a 264 amino acid (aa) type II transmembrane glycoprotein which belongs to the C-type lectin superfamily. It contains a 208 aa extracellular region with a single carbohydrate recognition domain (CRD) and a cytoplasmic segment (35 aa) bearing an immunoreceptor tyrosine-based activation motif (ITAM). In mice, CLEC9A is strictly expressed on CD8a-positive dendritic cells and plasmacytoid dendritic cells. It recognizes a ubiquitous preformed acid-labile protein associated ligand(s) that is exposed on necrotic cells. CLEC9A ligation is necessary for efficient cross-presentation of dead-cell-associated antigen by recruitment and activation of the tyrosine kinase Syk.