|Detection of Mouse FOLR4 by Western Blot. Western blot shows lysates of mouse CD+CD25+ regulatory T cells. PVDF Membrane was probed with 1 µg/mL of Sheep Anti-Mouse FOLR4 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF6124) followed by HRP-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # HAF016). A specific band was detected for FOLR4 at approximately 37 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 8.|
|Detection of FOLR4 in Mouse Splenocytes Gated on FoxP3 Cells by Flow Cytometry. Mouse splenocytes gated on FoxP3 cells treated with 10 μL/mL anti-CD3/anti-CD28, Recombinant Mouse IL-2 (Catalog # 402-ML), and Human TGF-beta 1 (Catalog # 100-B) for 3 days to induce T regulatory cells (Tregs) were stained with Sheep Anti-Mouse FOLR4 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF6124, filled histogram) or isotype control antibody (Catalog # 5-001-A, open histogram), followed by Allophycocyanin-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # F0127). To facilitate intracellular staining, cells were fixed and permeabilized with Flow Cytometry FoxP3 Staining Buffer (Catalog # FC011).|
FOLR4 (folate receptor 4; also FR4, FR‑δ and FOLBP‑3) is a 35 kDa glycoprotein member of the folate receptor family. It is found on mouse Treg cells, particularly those classified as natural and CD4+ CD25- T cells that produce low amounts of IFN-gamma. Its function is unclear. Although folate family receptors can internalize folate, they are generally not the principal conduits for folate uptake. Mouse FOLR4 preproprecursor is 244 amino acids (aa) in length. It contains a 19 aa signal sequence plus a 225 aa proform. While there are no definitive structural motifs, there is presumably a C-terminal propeptide that gives rise to a GPI-linkage. There are three potential isoforms. One is 37 kDa in size and shows a 36 aa insertion after Glu155. Two others show a deletion of aa 47‑109, and a 17 aa substitution for aa 157‑244. Over aa 20‑100, mouse FOLR4 shares 84% and 70% aa identity with rat and human FOLR4, respectively.