Overview
The DEAH-box, DEAD-box, and DExH-box families are collectively referred to
as the DExD/H family of proteins. DExD/H proteins are multifunctional
proteins that play important roles in virtually all aspects of RNA metabolism
such as RNA synthesis, processing, export, translation, turnover, and the
remodeling of ribonucleoprotein (RNP) complexes. DExD/H proteins act
principally as ATP-dependent helicases that function to unwind RNA
structures. They have also been reported to play an important role in
transcription; however this particular function, as well as the function of
RNP remodeling, appears to be independent of their helicase activity.
Although similar in structure within the helicase core, a considerable divergence
exists in the flanking domains of the DExD/H proteins. This divergence
likel y contributes to their multifunctional capabilities as well as their
specificity towards RNA substrates. The discovery that DExD/H proteins play
a role in transcription and interact with the transcriptional machinery
suggests a complex role involved in coupling the processes of transcription
and RNA processing. Due to their complexity, the human DExD/H family of
proteins is clearly emerging as an exciting area of research, and much work
remains to be done to elucidate the specific roles and regulation of the
more than 70 members of this protein family.
