Figure 5. Different types of mRNA movements depend on subcellular location and on cell type.

a | Different types of mRNA movements can be observed in neurons, including diffusive movement; active, motored transport; and stalling or anchoring of mRNAs. Whereas around the nucleus, mRNAs encoding β-actin seem to move in a diffusive manner, in dendrites β-actin and ARC mRNAs seem to be largely stalled or corralled, and 10% of dendritic mRNAs are seen to undergo active transport on microtubules^{58, 62, 100, 101}. b | In fibroblasts, most β-actin mRNAs are diffusing. A small percentage is transported along microtubules, and some mRNAs dwell near focal adhesions^{49, 58}. c | In budding yeast, ASH1 mRNAs are mostly diffusive. The localization of the ASH1 mRNA is accomplished through myosin-mediated transport to the bud tip, where the mRNA is anchored^{38, 39, 175}.d | oskar mRNAs in Drosophila melanogaster oocytes move around mostly in a diffusive manner. A small percentage can be seen moving along the cytoskeleton for brief lengths⁵⁴. At the posterior, oskar mRNAs are anchored. e | vg1 mRNAs in Xenopus laevis oocytes localize to the vegetal cortex owing to a bias in the placement of the plus ends of microtubules⁹⁴. This localization depends on two forms of kinesin, although the precise dynamics of vg1 mRNA movement are unclear.