KIR2DL4 (p58 KIR, CD158, KIR-103AS, Killer Cell Immunoglobulin (Ig)-like Receptor) (Carboxyfluorescein)

KIR2DL4 (2DL4, p49, CD158d, KIR103) is a type I transmembrane protein of the killer cell Ig-like receptor (KIR) family expressed on NK and subsets of gamma delta T and memory/effector alpha beta T cells. KIR2DL4 is a unique KIR;(1-3) alleles are not clonally restricted but are expressed codominantly (4) in all activated NK cells and constitutively on CD56hi NK cells. KIR members with two Ig-like domains (2D) usually express domains D1 and D2, but KIR2DL4 expresses D0 and D2. Other long-tailed (L) KIR have two cytoplasmic inhibitory signaling domains (ITIM), but KIR2DL4 has one ITIM and also exhibits characteristics of activating KIR (2). An arginine within the transmembrane sequence of KIR2DL4 interacts with the signaling molecule FceRI-g, while in activating KIR, a transmembrane lysine interacts with DAP12 (1,5). The KIR2DL4 gene is highly polymorphic. Seven splice variants missing one or more exons have been identified, but it is not clear whether these are expressed. Several of the nine alleles identified encode a frameshift creating a prematurely truncated protein; it is estimated that up to 25% of humans do not express KIR2DL4 capable of reaching the cell surface (1,7,10). KIR receptors have no structural orthologs in non-primates, although mouse Ly49 proteins are functional orthologs. Cross-linking of KIR2DL4 induces NK cells to produce IFN-g (6,7); stimulation with IL-2 upregulates cell surface expression on CD56dim cells and allows cytotoxicity (7). Applications: Suitable for use in Flow Cytometry. Other applications not tested. Recommended Dilution: Flow Cytometry: Neat. 10ul labels 1x10e5 cells. Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4 degrees C for short-term only. For long-term storage and to avoid repeated freezing and thawing, add sterile 40-50% glycerol, aliquot and store at -20 degrees C. Aliquots are stable for at least 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. CFS conjugates are sensitive to light.