Thioredoxin Related Transmembrane Protein 3 (TMX3)

The TMX3 gene encodes a protein of 454 amino acid residues that contains a predicted N-terminal signal sequence, a single domain with sequence similarity to thioredoxin and a CGHC active site sequence, a potential transmembrane domain, and a C-terminal KKKD tetrapeptide sequence that matches the classical KKXX-type consensus sequence for ER retrieval of type I transmembrane proteins. Endogenous TMX3 contains endoglycosidase H-sensitive glycans, localizes to the ER by immunofluorescence microscopy, and is present in the membrane fraction after alkaline extraction of the ER luminal content. The TMX3 transcript is found in a variety of tissues and is not up-regulated by the unfolded protein response.