Dead-box proteins: a family affair--active and passive players in RNP-remodeling

Abstract

DEAD-box proteins are characterized by nine conserved motifs. According to these criteria, several hundreds of these proteins can be identified in databases. Many different DEAD-box proteins can be found in eukaryotes, whereas prokaryotes have small numbers of different DEAD-box proteins. DEAD-box proteins play important roles in RNA metabolism, and they are very specific and cannot mutually be replaced. In vitro, many DEAD-box proteins have been shown to have RNA-dependent ATPase and ATP-dependent RNA helicase activities. From the genetic and biochemical data obtained mainly in yeast, it has become clear that these proteins play important roles in remodeling RNP complexes in a temporally controlled fashion. Here, I shall give a general overview of the DEAD-box protein family.

Figure 1

A schematic presentation of the conserved motifs of the DEAD-box family. (A) Consensus sequence of the DEAD-box family. Residues identified in the structure of the Vasa protein (70) to interact with ATP (red), RNA (blue) or involved in intra-protein interactions (green) are highlighted. (B) Consensus sequences of the DEAH-box and Ski2 family. The consensus sequences (capital letters represent amino acids conserved at least 80%, lower case letters represent amino acids that are conserved 50–79%) are taken from Tanner and Linder (10).

Figure 2

Schematic presentation of cellular processes that require DEAD-box proteins in eukaryotic cells.