Toll receptors trigger immune responses through adaptor proteins and kinase enzymes. Structural studies reveal that hierarchical assembly of these proteins into a helical tower initiates downstream signalling events.

Toll-like receptors (TLRs) are crucial to innate immunity. Activation of these proteins, and of receptors for the pro-inflammatory cytokines IL-1 and IL-18, leads to the recruitment of adaptor proteins such as MyD88. These in turn interact with further proteins such as IRAK2 and IRAK4. The crystal structure of the MyD88–IRAK2–IRAK4 death domain complex is now reported, explaining how these three proteins cooperate in TLR/IL-1R signalling.

KBO 55636 (2002 TX300) is one of the Kuiper belt objects — specifically, a member of the water-ice-rich Haumea KBO collisional family. Here, observations are reported of a multi-chord stellar occultation by KBO 55636. Calculations show that KBO 55636 is smaller than previously thought and, like its parent body, is highly reflective. The dynamical age implies either that it has an active resurfacing mechanism, or that fresh water-ice in the outer Solar System can persist for gigayear timescales.