MW: 21.9 kDa. Purity >98% by SDS-PAGE and HPLC. APRIL (a proliferation inducing ligand), also known as TNFSF13, TALL2, and TRDL1, is a member of the TNF ligand superfamily. It is synthesized as a 32 kDa type II transmembrane protein which is cleaved by furin in the Golgi to release a 17 kDa soluble molecule. Secreted APRIL consists almost entirely of a single TNF homology domain. Little or no transmembrane APRIL is expressed on the cell surface. Alternate splicing generates isoforms with short d