DAP12 is a 12 kDa transmembrane protein recently recognized as a key signal
transduction receptor element in Natural Killer (NK) cells. It is a disulf
ide-linked homodimer that non-covalently associates with several activating
receptors expressed on NK cells, Activation signals initiated through DAP1
2 are predicted to play strategic roles in triggering NK cell cytotoxicity
responses toward certain tumor cells and virally infected cells. The cytopl
asmic domain of DAP12 contains an Immunoreceptor Tyrosine-based Activation
Motif (ITAM). Phosphorylation of ITAM tyrosines mediates associations with
protein tyrosine kinases, which is a resonant feature of signalling through
these motifs in T and B cell antigen receptors. In addition, its expressio
n in other tissues, including dendritic cells and monocytes, suggests that
DAP12 transduces ITAM-mediated activation signals for an extended array of
receptors in those cells as well. (C) 1999 Elsevier Science Ltd. All rights
reserved.