Sugar molecules bound to RNA may be playing a new—and as-yet-unknown—role in controlling immune reactions, The Scientist reports. The molecules, called glycans, were already known to bind to proteins and lipids, where they help control chemical signaling between cells (particularly immune signaling) when the sugar-tagged molecules migrate to the cell surface. But as Science reported in 2019, researchers found that glycans could also bind to strands of RNA, which normally translate genetic information into proteins and catalyze chemical reactions. The new finding, reported yesterday in Cell, suggests glycoRNAs also migrate to cell surfaces, where they may be involved in cell-to-cell communication.