How and why does Dia1 mRNA localize?

Messenger RNA (mRNA) localization plays an important role in various cellular functions. To date, two general mechanisms have been identified for intracellular mRNA localization. The first one was identified by Blobel and colleagues more than three decades ago, by which mRNAs encoding for membrane and secreted proteins are targeted to the endoplasmic reticulum (ER) in a signal peptide dependent manner.1 The second mechanism is for the intracellular targeting of mRNAs encoding cytosolic proteins, which is dependent on specific sequence on the mRNA called zipcode.2 Recently, we have identified a new mechanism which targets Dia1 mRNA to the perinuclear ER in a zipcode-independent manner, even though the mRNA encodes a cytosolic protein.3 Here, we provide an updated discussion on how the Dia1 mRNA is targeted and what might be its physiological significance.