KIR3DS1, Fc Chimera, Recombinant, Human (Killer Cell (Ig)-like Receptor 3DS1, Natural Killer-Associated Transcript 10, NKAT-10)

KIR3DS1 (3DS1, CD158e2) is a type I transmembrane protein that belongs to the killer cell Ig-like receptor (KIR) family. KIRs are expressed on CD56 dim NK cells and T cell subsets where they differentiate normal from abnormal cells, and regulate effector functions in the innate immune system. 1-3 KIRs are named for the number of Ig-like domains (2D or 3D) in the extracellular domain (ECD), and whether they have long or short (L, S) cytoplasmic tails. Like other activating KIRs, KIR3DS1 has a short cytoplasmic tail and a positively charged amino acid (aa) within the transmembrane domain that interacts with the ITAM-bearing signaling adaptor, DAP12. 2, 4 Crosslinking of KIR3DS1 activates cytolysis and induces IFN-g production, confirming it to be an activating receptor. 4 Approximately 38% of the population expresses KIR3DS1 on the surface of NK cells. 1, 4, 5 Variants lacking the N-terminal Ig-like domain and/or with substitutions in the cytoplasmic tail have been described. 1, 6 The 50 kD, 387 aa KIR3DS1 shows 97% aa identity with KIR3DL1 within the ECD, and the two segregate as alleles. 3, 7 Some activating KIRs bind weakly to the ligands recognized by their corresponding inhibitory KIR. KIR3DS1 does not bind appreciably to cells transfected with ligands for HLA-Bw4 KIR3DL1. 4, 5 However, HIV-infected people who express the combined phenotype of KIR3DS1 with Bw4 alleles that contain an isoleucine at aa 80, show delayed progression to AIDS and fewer AIDS-related opportunistic infections. 7, 8 KIR receptors have no structural orthologs in nonprimates, although mouse Ly-49 proteins perform similar functions. 2\n\nSource: Human CD33 Signal peptide (Met 1-Ala 16), Human KIR3DS1, (His 22-His 340) IEGRMD, Human IgG1 (Pro 100-Lys 330); A DNA sequence encoding the extracellular domain of human KIR3DS1 (His 22-His 340; Accession # Q14943) was fused to the human CD33 signal peptide at the N-terminus and the Fc region of human IgG1 via a linker peptide at the C-terminus. The protein was expressed in a CHO cell line.\n\nMolecular Mass: The recombinant human KIR3DS1/Fc chimera is a disulfide-linked homodimeric protein. Based on N-terminal sequencing, the recombinant protein starts at His 22. Each monomer has a calculated molecular mass of 61.9 kD. As a result of glycosylation, the recombinant protein migrates as an approximately 75-90 kD protein in SDS-PAGE under reducing conditions.\n\nEndotoxin Level: < 1.0 EU per 1 microg of the protein as determined by the LAL method.\n\nActivity: Measured by its ability to bind MDA-MB231 cells. As determined by flow cytometery analysis, there is a 200-500 fold increase in fluorescence intensity of MDA-MB231 cells stained with 3microg/mL rhKIR3DS1/Fc and goat anti-human Fc-PE as compared to cells stained with goat anti-human Fc-PE.\n\nReconstitution: It is recommended that sterile PBS be added to the vial to prepare a working stock solution of no less than 100ug/ml. The carrier-free protein should be used immediately upon reconstitution to avoid losses in activity due to non-specific binding to the inside surface of the vial. For long term storage as a dilute solution, a carrier protein (e.g. 0.1% HSA or BSA) should be added to the vial.\n\nStorage and Stability: Lyophilized samples are stable for up to twelve months at -20 degrees C. Upon reconstitution, this protein, in the presence of a carrier protein, can be stored under sterile conditions at 2 degrees -8 degrees C for one month or at -20 degrees C in a manual defrost freezer for three months without detectable loss of activity. Avoid repeated freeze-thaw cycles.

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SPECIFICATIONS

Catalog Number

K1862-38

Size

50ug

Form

Supplied as a lyophilized powder in PBS.

Purity

(same/more than) 90% as determined by SDS-PAGE and visualized by silver stain.

References

1. Dohring, C. et al., 1996, Immunogenetics 44:227. \n2. Lanier, L. L., 2005, Annu. Rev. Immunol. 23:225. \n3. Uhrberg, M. et al., 1997, Immunity 7:753-763. \n4. Carr, W. H. et al., 2007, J. Immunol. 178:647. \n5. O