Application Methods: Flow Cytometry, Immunofluorescence (Immunocytochemistry), Immunoprecipitation, Western Blotting
Background: DC-SIGN (CD209, CLEC4L) is a C-type lectin receptor expressed by dendritic cells (DCs) (1,2). The DC-SIGN transcript can undergo several splicing events to generate at least thirteen different transmembrane and soluble isoforms (3). DC-SIGN responds to a broad range of pathogens due to its ability to recognize both mannose and fructose carbohydrates, and is well studied for its role in HIV infection. Recognition of the HIV envelope glycoprotein gp120 by DC-SIGN leads to internalization of HIV by DCs and facilitates transmission of the virus to CD4+ T cells (2,4). DC-SIGN also mediates adhesion to T cells through interaction with ICAM-3, as well as transmigration across the endothelium by binding to ICAM-2 (1,5). The DC-SIGN receptor can modulate TLR signaling by activating the kinase Raf-1 (6,7). The closely related molecule DC-SIGNR (L-SIGN, CLEC4M) is 77% homologous to DC-SIGN and likely arose through a gene duplication event (8). Like DC-SIGN, DC-SIGNR binds mannose carbohydrates on the surface of pathogens (8,9). However, the expression patterns of the two receptors differ, as DC-SIGNR expression is restricted to endothelial cells of the liver, lymph node, and placenta (10). Murine cells contain a set of related molecules, SIGNR1-SIGNR8 (11). Based on sequence analysis, there is no clear murine ortholog to human DC-SIGN, however SIGNR3 is the most functionally similar due to its ability to recognize both mannose and fructose structures (11).
|Human, Monkey, Mouse, Rat|
Application Methods: Immunofluorescence (Immunocytochemistry), Immunohistochemistry (Paraffin), Western Blotting
Background: Secretory proteins are synthesized on polysomes and translocated into the endoplasmic reticulum (ER). Inside ER, these proteins are often modified by disulfide bond formation, amino-linked glycosylation and folding. The ER contains a pool of molecular chaperones, including Grp94, to help ensure correct protein folding. Grp94 is a glucose-regulated protein (1) with sequence homology to Hsp90 (2). In addition to its role in helping to facilitate folding of a number of secretory proteins to their correct conformation (3), studies suggest that Grp94 derived from cancer cells also induces anti-tumor immune responses in mouse tumor models (4, 5). One way in which Grp94 promotes tumor immunogenicity is its ability to bind to and present tumor-derived peptides as antigens (6). Furthermore, Grp94 has also been shown to induce maturation of dendritic cells (7). Taken together, Grp94 functions both as a tumor-specific antigen and as an activator of antigen-presenting cells to elicit an anti-cancer immune response (8).