Extending the 'stressy' edge: molecular chaperones flirting with RNA.

A number of intriguing observations have emerged during the past years indicating that certain classes of the evolutionarily highly conserved heat shock or stress proteins extend their molecular partnerships beyond the originally recognized protein world. In this review, following a brief introduction to the 70-kDa family of stress proteins, we summarize the main aspects of RNA recognition and binding by this class of molecules. By highlighting some biochemical features of both the protein and RNA partners, we attempt to embed the central parts of this interaction in the context of potential physiological relevance. As perhaps true for many newly recognized molecular interactions, the phenomenon of RNA recognition and binding by molecular chaperones discussed in this review calls for a place of ever-growing importance in the functional genomic era, where an expanding number of previously unsuspected molecular partnerships are uncovered by virtue of powerful high throughput methodologies. We suggest that integration of this new knowledge into the long-outlined 'classical' network of cellular metabolism at both the biochemical and architectural level is pivotal to the emerging 'synthesis era' of today's cell biology.