How Molecules Get to the Right Place at the Right Time

In a multicellular organism, different cells fulfill a range of diversified functions. Often such specialization depends on the delivery of molecular goods to distinct places within a cell. It ensures that particular functions only occur at defined cellular sites. This establishment of intracellular asymmetry in the otherwise fluid environment of the cell cytoplasm requires active transport processes. Messenger RNAs (mRNA) represent an especially important type of freight.
All cells containing a nucleus also possess a cytoskeleton made up of filamentous protein strands that course through intracellular space like a rail network. Motor proteins "walk" along two types of these strands, called actin filaments and microtubules. On their way, they can carry different types of freight like membrane vesicles, messenger RNAs, proteins and even whole organelles. Disruption of these networks can cause chaos and may result in cell death. The motor proteins must recognize and bind to the correct fiber system and to the appropriate cargo. For transport of freight, molecular motors interact with a plethora of accessory factors to form large transport complexes.

Journal Reference:

1. Marisa Müller, Roland Gerhard Heym, Andreas Mayer, Katharina Kramer, Maria Schmid, Patrick Cramer, Henning Urlaub, Ralf-Peter Jansen, Dierk Niessing. A Cytoplasmic Complex Mediates Specific mRNA Recognition and Localization in Yeast. PLoS Biology, 2011; 9 (4): e1000611 DOI: 10.1371/journal.pbio.1000611