|Detection of Human TIN-Ag by Western Blot. Western blot shows lysates of human kidney (cortex and medulla) tissue. PVDF Membrane was probed with 1 µg/mL of Sheep Anti-Human TIN-Ag Antigen Affinity-purified Polyclonal Antibody (Catalog # AF6797) followed by HRP-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # HAF016). A specific band was detected for TIN-Ag at approximately 55-60 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 1.|
TIN-Ag (Tubulointerstitial nephritis antigen) is a 48-58 kDa glycoprotein member of the peptidase C1 family of molecules. It is secreted by renal tubule epithelium and (presumably) small intestine columnar epithelium. TIN-Ag is an integral component of the renal tubule basement membrane (BM), and appears to promote proper BM matrix organization, block laminin polymerization, and serve as a receptor for the epithelial integrins alpha 3 beta 1 and alpha v beta 3. Epithelial dissociation from the BM is associated with an epithelial-to-mesenchymal transition. Human TIN-Ag is synthesized as a 476 amino acid (aa) preproprecursor. It contains a 19 aa signal sequence, a 30 aa furin-cleavable prosegment (aa 20-49), and a 427 aa mature region (aa 50-476). Within the mature region is an SMB domain (aa 61-106), one vWFC domain (aa 119‑154), and a nonenzymatic peptidase C1A region (aa 218-466). Multiple splice variants are possible, and potential isoforms may show an alternative start site at Met322, or a combined deletion of aa 119‑169 plus 209-300, or a combination of an alternative start site at Met19 coupled to a 13 aa substitution for aa 209-476. Over aa 20-476, human proTIN-Ag shares 86% aa identity with mouse proTIN-Ag; over the mature region (aa 50-476), human TIN-Ag shares 89% aa identity with mouse TIN-Ag.