A
transmembraneglycoprotein, NSP4 is organized into three main domains: a three-helical TM domain in the
N-terminus (also a
viroporin domain), a central
cytoplasmic coiled-coil domain for
multimerization, and a C-terminal flexible region. It can also be secreted out of the cell. As of 2019, only structures of the central domain, which is responsible for diarrhea, has been solved. It
oligomerizes into
dimeric,
tetrameric,
pentameric, and even higher-order forms.[4]