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. Author manuscript; available in PMC: 2014 Jan 1.
Published in final edited form as: Traffic. 2012 Sep 13;14(1):2–14. doi: 10.1111/tra.12004

Figure 2. A schematic view of the multistep process for mRNA localization.

Figure 2

Mechanistic studies in different model systems reveal that mRNA localization is a multi-step process involving the assembly of mRNP granules, engagement of transport molecular motors and subsequent active transport and anchorage of mRNPs at the destination. (1) Assembly of transport mRNP granules can initiate from the nucleus, coupled to transcription and splicing. The binding of mRNA-binding proteins to nascent pre-mRNAs may help to maintain mature mRNAs in a translational quiescent state. EJCs are loaded onto mature mRNAs following the incision of introns. (2) mRNPs are exported into the cytoplasm. (3) mRNA-binding proteins interacting with zipcode elements recruit transport machineries by direct or indirect interaction with molecular motors including myosin, kinesin and dynein/dynactin complexes for microfilament or microtubule-mediated cargo transport. (4) Molecular motors couple mRNPs to microfilaments or microtubules for active transport. Molecular motor-mediated mRNA transport and localization requires intact cytoskeletal structures. (5) mRNPs are anchored to their destination. (6) Properly targeted and repressed mRNAs are released for local translation in response to local signaling events.