Intramembrane-cleaving aspartic protease (I-CLiP) that cleaves type II membrane signal peptides in the hydrophobic plane of the membrane. Functions in ITM2B and TNF processing (PubMed:16829952, PubMed:16829951, PubMed:17965014, PubMed:19114711, PubMed:22194595). Catalyzes the intramembrane cleavage of the anchored fragment of shed TNF-alpha (TNF), which promotes the release of the intracellular domain (ICD) for signaling to the nucleus (PubMed:16829952, PubMed:16829951). May play a role in the regulation of innate and adaptive immunity (PubMed:16829952). Catalyzes the intramembrane cleavage of the simian foamy virus processed leader peptide gp18 of the envelope glycoprotein gp130 dependently of prior ectodomain shedding by furin or furin-like proprotein convertase (PC)-mediated cleavage proteolysis (PubMed:23132852). Monomer (PubMed:15998642, PubMed:16873890). Homodimer (PubMed:15998642, PubMed:16873890). Interacts with ITM2B (PubMed:17965014). Interacts with TNF (PubMed:16829951). Interacts with the simian foamy virus envelope glycoprotein gp130 and its processed leader peptide gp18LP; preferentially interacts with the leader peptide gp18LP (PubMed:23132852). targeted through the entire secretory pathway to endosomes/lysosomes (PubMed:15998642). Experimental confirmation may be lacking for some isoforms. Expressed predominantly in adrenal cortex and mammary gland. The PAL motif is required for normal active site conformation. The catalytic domains embedded in the membrane are in the opposite orientation to that of the presenilin protein family; therefore, it is predicted to cleave type II-oriented substrate peptides like the prototypic protease SPP. Glycosylated (PubMed:15385547, PubMed:15998642). Belongs to the peptidase A22B family. Extended N-terminus. Extended N-terminus. Wrong choice of frame. Probable cloning artifact.