Abstract
The Retention Using Selective Hooks (RUSH) system allows for the synchronized release of one or more proteins of interest from a donor endomembrane compartment, usually the endoplasmic reticulum, and the subsequent monitoring of their traffic toward acceptor compartments. Here we describe the RUSH system applied to cytotoxic T cells to characterize the biogenesis of lytic granules, using as a proof-of-concept granzyme B trafficking to this specialized compartment.