Active transport of mRNAs from the nucleus (left, light blue)to peripheral cytoplasmic destination sites in eukaryotic cells. Transport proceeds through a number of sequential phases as follows: (a) Recognition of cis-acting elements by nuclear trans-acting factors (TAFs) (purple ellipses) and formation of ribonucleotide protein (RNP) complexes; (b) nuclear export of RNP particles and recruitment of cytoplasmic TAFs ( yellow ellipses); (c) motor-based active transport of cytoplasmic RNP particles along cytoskeletal filaments (green and blue lines); (d, f ) association with additional cytoplasmic TAFs, such as anchoring proteins, at destination sites (light green ellipses); (e, f ) recruitment of ribosomes and other translational components (not shown) either before (e)or after ( f ) cytoplasmic translocation; ( g) locally controlled translation.