Signalosome


Signalosomes are large supramolecular protein complexes that undergo clustering and/or colloidal phase separation to form biomolecular condensates that increase the local concentration and signalling activity of the individual components. They are an example of molecular self-assembly and self-organisation in cell biology.

Examples

Wnt signalosome: Transduction of Wnt signals from the plasma membrane depends on clustering of LRP6 receptors with Dishevelled proteins to recruit the Axin complex for inactivation.
B-cell receptor signalosome: The B-cell receptor binds antigen and undergoes clustering to induce signal transduction.
T-cell receptor signalosome: Antigen presentation to T-cells is recognised by the T-cell receptor, which initiates clustering and activation of downstream signalling to induce T-cell responses.
COP9 signalosome: Catalyses the hydrolysis of NEDD8 protein from the Cullin subunit of Cullin-RING ubiquitin ligases. Therefore, it is responsible for CRL deneddylation – at the same time, it is able to bind deneddylated cullin-RING complex and retain them in deactivated form. COP9 signalosome thus serves as a sole deactivator of CRLs.
RIP1/RIP3 Necrosome: A signalling complex involved in necrotic cell death.