Potential role in vesicular protein trafficking, mainly in the early secretory pathway. May act as a cargo receptor at the lumenal side for incorporation of secretory cargo molecules into transport vesicles and may be involved in vesicle coat formation at the cytoplasmic side. Plays a positive role in IL-33-mediated IL-8 and IL-6 production by interacting with interleukin-33 receptor IL1RL1. Plays also a role in the modulation of innate immune signaling through the cGAS-STING pathway by interacting with RNF26. Homodimer in endoplasmic reticulum, endoplasmic reticulum-Golgi intermediate compartment and cis-Golgi network. Interacts with IL1RL1. Interacts with RNF26; this interaction is important to modulate innate immune signaling through the cGAS-STING pathway. Widely expressed. Belongs to the EMP24/GP25L family.