Biolegend, 591309, Recombinant Human APRIL (TNFSF13) (ELISA Std.)

This product is not available for shipping outside of the United States. APRIL (A Proliferation-Inducing Ligand), also known as TNFSF13, stimulates cell proliferation. It is a member of the TNF superfamily of ligands, being most closely related to BAFF, with which it shares 30% amino acid sequence identity. APRIL is cleaved intracellularly by furin and is believed to exist mainly in a secreted, soluble form. As with most other TNF family members, APRIL exists as a functional homotrimer (total MW = 90 kD). It can bind to two cell-surface receptors: BCMA and TACI, which it shares with BAFF, to exert downstream T- and B-cell regulatory effects. It also possesses a heparin binding domain and has been demonstrated to bind to proteoglycans on the cell surface. APRIL is most well known for its tumor proliferation effects. It is a potential biomarker, with serum levels elevated for certain cancers and expression levels elevated in cancer tissues. It is also a potential biomarker for certain autoimmune diseases. In fact, recombinant TACI has been brought to clinical trials as a neutralization drug against APRIL and BAFF for the treatment of systemic lupus erythematosus (SLE). Besides forming homotrimers, APRIL can also form functional heterotrimers with BAFF. The stoichiometric relationship of the protomeric units is still unclear; however, it appears that these heterotrimers are significant in that they are elevated in the serum of certain autoimmune patients. APRIL also forms an endogenous chimeric protein with another related protein, TWEAK, effectively called TWE-PRIL. It is believed that TWE-PRIL is membrane bound, and consists of the N-terminus of TWEAK with its transmembrane domain, and the C-terminus of APRIL with its receptor binding domain.