Entry into the secretory system--the role of mRNA localization

In addition to protein targeting mechanisms, proteins may also be targeted to specific subcellular compartments by localization of their mRNAs. mRNA localization, which is a more cost-effective mechanism than protein targeting, can control assembly of macromolecular structures within the cell, aid in the formation of endoplasmic reticulum subdomains, facilitate protein localization in the endomembrane system and control gene expression. In addition, mRNA localization in plants is likely to be an important mechanism for controlling intercellular communication not only between adjacent cells but those separated by relatively long distances. Although mRNAs can be localized by different mechanisms, evidence gathered to date implicate the role of cytoskeletal elements, microfilaments and microtubules, in the transport and anchoring of RNAs to specific subcellular locations within the cell.