Torsin3A is a 397 amino acid member of the clpA/clpB family of proteins. Localized to the cytoplasm and the endoplasmic reticulum，Torsin3A is most highly expressed in stomach，lymph nodes and salivary glands. Torsin3A contains a hydrophobic N-terminal sequence，an ATP binding domain and 8 putative phosphorylation sites. Highly homologous with TorsinA and TorsinB，Torsin3A is thought to be related to the AAA chaperone-like family of ATPases. Members of this family play a role in the assembly，disassembly and operation of a variety of protein complexes，confer increased tolerance to high temperature and promote specific proteolysis. Torsin3A is also referred to as an interferon responsive gene，as interaction with type 1 interferons (IFN-alpha and IFN-beta) cause a 5 to 40 fold increase in Torsin3A mRNA levels. Three isoforms of Torsin3A exist as a result of alternative splicing events，and isoform 2 is expressed exclusively in the placenta