|Detection of Human Latent TGF‑ beta bp2/LTBP‑2 by Western Blot. Western blot shows lysates of HFL1 human fetal lung fibroblast cell line and human heart tissue. PVDF membrane was probed with 1 µg/mL of Goat Anti-Human Latent TGF‑ beta bp2/LTBP‑2 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF3850) followed by HRP-conjugated Anti-Goat IgG Secondary Antibody (Catalog # HAF017). A specific band was detected for Latent TGF‑ beta bp2/LTBP‑2 at approximately 210-255 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 1.|
LTBP-2 (Latent TGF-beta Binding Protein 2; also C14orf141) is a 220-250 kDa secreted glycoprotein member of the LTBP family of proteins. In SDS-PAGE and under reducing conditions, LTBP-2 runs at 220-250 kDa; under nonreducing conditions, LTBP-2 runs between 205-220 kDa. Although it is described as being a TGF-beta binding protein, it does not possess the ability to bind covalently to TGF-beta. Instead, it appears to bind to heparin sulfate moieties on syndecan-4 and perlecan, plus fibrillin-1 and fibulin-5, suggesting a role in both elastic fiber formation and the maintenance of basement membrane integrity. In addition, LTPB-2 is now known to form a complex with PC5/6A intracellularly, and upon secretion, dampen PC5 activation in the extracellular environment. Cells known to express LTBP-2 include lens and nonpigmented ciliary epithelium, fibroblasts, vascular smooth muscle and chondrocytes. Mature human LTBP-2 is 1786 amino acids (aa) in length (aa 36-1821). It possesses three heparin-binding regions (aa 94-115, 232-249, and 344-354), plus 20 EGF-like domains (aa 187-1818) that contain four interspersed TGF-beta type binding segments. Over aa 36-1821, human LTBP-2 shares 80% aa sequence identity with mouse LTBP-2.