Human Reg4 Alexa Fluor™ Plus 555-conjugated Antibody

Reg4 (regenerating islet-derived protein 4; also named Reg-like protein, RELP, and gastrointestinal secretory protein) is a 17 kDa, secreted glycoprotein belonging to the calcium (C-type) dependent lectin superfamily and the regenerating gene family (1‑3). There are three potential isoforms for human Reg4. Isoform 1 is synthesized as a 158 amino acid (aa) precursor with a 22 aa signal sequence and a 136 aa mature chain. Amino acids 30‑156 constitute a C-type lectin-like domain, and aa 50 is a site for potential N-linked glycosylation. In addition, amino acids 127 and 142‑143 form a ligand-binding surface. In isoform 2, there is a 79 aa substitution for the C-terminal 101 amino acids, while in isoform 3, there is an 11 aa substitution for the C‑terminal 57 amino acids. Human Reg4 shares 68% and 67% aa sequence identity with rat and mouse Reg4, respectively. Like other members of the regenerating gene family, Reg4 is expressed in the gastrointestinal (GI) tract and ectopically at other sites in the setting of tissue injury (1, 2). In particular, Reg4 is expressed in normal colon mucosa, and up‑regulated in colon adenocarcinoma, pancreatic cancer, gastric adenocarcinoma, inflammatory bowel disease (Crohn’s disease and ulcerative colitis), and, outside the GI tract, in prostate adenocarcinoma (2‑8). The physiological function of Reg4 is presently unknown, but it may be involved in inflammatory and metaplastic responses of the GI epithelium (3).