In this week's Science, a group of Max Planck Institute of Biochemistry researchers describe a new high-resolution mass spectrometric method for identifying and quantifying secreted proteins, demonstrating it on proteins released from immune cells upon receptor ligation. The work "enables a systematic dissection of signaling pathways and the identification of proteins with transcriptionally independent or unexpected extracellular functions," the researchers write.
Also in Science, Massachusetts Institute of Technology scientists Jeremy Wilusz and Phillip Sharp provide an overview of circular RNAs, which had previously only been found in pathogens, but recently have been discovered in a range of species, including humans. One circular RNA in particular is highly abundant in human brains and contains dozens of binding sites for a particular microRNA, miR-7. Because circular RNAs generally have multiple microRNA binding sites, Wilusz and Sharp suggest that other circular RNAs may also regulate the activity of microRNAs. They also propose that circular RNAs may act to bind and sequester RNA-binding proteins or "even base pair with RNAs besides microRNAs, resulting in the formation of large RNA-protein complexes."