May be involved in membrane trafficking in the early secretory pathway. Inhibits BACE1 activity and amyloid precursor protein processing. May induce caspase-8 cascade and apoptosis. May favor BCL2 translocation to the mitochondria upon endoplasmic reticulum stress (PubMed:24262037). Induces the formation of endoplasmic reticulum tubules. Acts also as an inflammation-resolving regulator by interacting with both TRIM25 and RIG-I/DDX58, subsequently impairing DDX58 'Lys-63'-linked polyubiquitination leading to IRF3 and NF-kappa-B inhibition (By similarity). Homodimer. Interacts with RTN4. Isoform 3 interacts with BACE1, BACE2, BCL2 and FADD (By similarity). Interacts with ATL1 and ATL2 (PubMed:19665976). Isoform 3 interacts with TMEM33 (PubMed:25612671). Interacts with ZFYVE27 and with KIF5A in a ZFYVE27-dependent manner (By similarity). Interacts with DDX58 (By similarity). Interacts with TRIM25 (By similarity). Isoform 1, isoform 3, isoform 4 and isoform 5 are expressed in spinal cord. Isoform 1 is present in brain, where it is expressed in the neurons of cerebral cortex, hippocampus, hypothalamus and cerebellum (at protein level).