Centrosomes deliver the death blow

Just as a deadly martial arts master channels his inner chi to deliver a fatal strike, cytotoxic T cells (CTLs) channel their toxic secretory granules to strike an infected target cell. New work by Jane Stinchcombe, Gillian Griffiths, and colleagues (Sir William Dunn School of Pathology, Oxford, UK) reveals that centrosomes do this channeling, going right to the plasma membrane to deliver their secretory granule death blows.

A CTL targets an infected cell by making transitory contact via an immunological synapse. Lytic protein–containing secretory granules are then released at the synapse to kill the target. Trafficking of the granules to the synapse was known to require transport along microtubules, but just how granules were delivered was unknown.

The general assumption was that CTLs would deliver their secretory granules in...