The TMX3 family proteins are probable disulfide isomerases involved in the folding of proteins with disulfide bonds. They may function as dithiol oxidases and play a role in regulating redox signals. Members of the TMX3 family are also implicated in maintaining endoplasmic reticulum-mitochondria contact sites, which are crucial for cellular homeostasis and signaling. The presence of a di-lysine motif in these proteins suggests their localization to the endoplasmic reticulum, which is typical for type I membrane proteins. The TMX3 family is part of the larger protein disulfide isomerase family, which is essential for the proper formation of disulfide bonds in nascent proteins, thereby ensuring correct folding and functionality.
