Diversity and selectivity in mRNA translation on the endoplasmic reticulum.
Pioneering electron microscopy studies defined two primary populations of ribosomes in eukaryotic cells: one freely dispersed through the cytoplasm and the other bound to the surface of the endoplasmic reticulum (ER). Subsequent investigations revealed a specialized function for each population, with secretory and integral membrane protein-encoding mRNAs translated on ER-bound ribosomes, and cytosolic protein synthesis was widely attributed to free ribosomes. Recent findings have challenged this view, and transcriptome-scale studies of mRNA distribution and translation have now demonstrated that ER-bound ribosomes also function in the translation of a large fraction of mRNAs that encode cytosolic proteins. These studies suggest a far more expansive role for the ER in transcriptome expression, where membrane and secretory protein synthesis represents one element of a multifaceted and dynamic contribution to post-transcriptional gene expression.
Program in Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore.
David W
DW
Reid
Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Christopher V
CV
Nicchitta
D000818:Animals; D004721:Endoplasmic Reticulum / Q000235:genetics*; D014644:Genetic Variation; D006801:Humans; D008954:Models, Biological; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*
D012333:RNA, Messenger