mRNA-based protein targeting to the endoplasmic reticulum and chloroplasts in plant cells

• Specific mRNAs are localized to distinct ER subdomains in rice endosperm.
• mRNA localization involves actin-mediated transport of a large RNP complex.
• mRNA targeting to ER subdomains may be involved in organellar biogenesis.
• Co-translation and directed import of mRNAs contribute to chloroplast protein targeting.

The targeting of proteins to subcellular organelles is specified by the presence of signal/leader peptide sequences normally located on the N-terminus. In the past two decades, messenger RNA (mRNA) localization, a pathway driven by cis-acting localization elements within the RNA sequence, has emerged as an alternative mechanism for protein targeting to specific locations in the cytoplasm, on the endoplasmic reticulum or to mitochondria and chloroplasts. In this review, we will summarize studies on mRNA-based protein targeting to the endoplasmic reticulum and chloroplast within plant cells.