Signal Peptide Peptidase Like 2B (SPPL2B)

SPPL2B encodes a member of the GXGD family of aspartic proteases. The GXGD proteases are transmembrane proteins with two conserved catalytic motifs localized within the membrane-spanning regions. This enzyme localizes to endosomes, lysosomes, and the plasma membrane. It cleaves the transmembrane domain of tumor necrosis factor alpha to release the intracellular domain, which triggers cytokine expression in the innate and adaptive immunity pathways. Multiple transcript variants encoding different isoforms have been found for this gene. The deduced protein contains 592 amino acids. Like other IMP proteins, IMP4 contains an N-terminal protease-associated (PA) domain, several transmembrane regions, a hydrophilic loop, conservative sequences around the first and second aspartate residues, and an invariant PAL motif near the C terminus.