Growing evidence demonstrates the importance of regulating mRNA localization, stability and translation, in the control of gene expression, both in development and in differentiated cells. The signals responsible for specific regulation of mRNA metabolism reside in the RNA message itself: both 5' and 3' to the coding region, all transcripts contain variable lengths of untranslated sequences (5'-UTR and 3'-UTR) which contain the binding sites for a number of RNA-binding proteins (RBPs). Most RBPs assemble on the message at the moment of transcription, thus determining the future fate of the transcript from the very beginning. We discuss possible mechanisms through which mRNA, leaving from the nucleus as an RNA-protein complex, might reach its final intracellular destinations and how its access to the translational apparatus might be regulated in time and space. We also focus on a few known examples of aberrant RNA-protein interactions associated with human diseases, including cancer.