DDX3 belongs to the DEAD-box proteins, a large family of ATP-dependent RNA 
helicases that participate in all aspects of RNA metabolism. Human DDX3 is a 
component of several messenger ribonucleoproteins that are found in the 
spliceosome, the export and the translation initiation machineries but also in 
different cytoplasmic mRNA granules. DDX3 has been involved in several cellular 
processes such as cell cycle progression, apoptosis, cancer, innate immune 
response, and also as a host factor for viral replication. Interestingly, not 
all these functions require the catalytic activities of DDX3 and thus, the 
precise roles of this apparently multifaceted protein remain largely obscure. 
The aim of this review is to provide a rapid and critical overview of the 
structure and functions of DDX3 with a particular emphasis on its role during 
mRNA metabolism.