Why cells move messages: The biological functions of mRNA localization

RNA localization is a widespread mechanism that allows cells to spatially control protein function by determining their sites of synthesis. In embryos, localized mRNAs are involved in morphogen gradient formation or the asymmetric distribution of cell fate determinants. In somatic cell types, mRNA localization contributes to local assembly of protein complexes or facilitates protein targeting to organelles. Long-distance transport of specific mRNAs in plants allows coordination of developmental processes between different plant organs. In this review, we will discuss the biological significance of different patterns of mRNA localization.