In an independent line of research, we use the secretory pathway as a model system to study the impact of alternative splicing on a fundamental cell biological process. We have discovered the first connection of alternative splicing and the secretory pathway and showed that activated T cells increase their secretory capacity through a splicing-based adaptation of the COPII machinery (Wilhelmi et al., Nat Comm, 2016). We then went on and combined bioinformatics with cell biology to provide the first global view of how alternative splicing controls membrane trafficking (Neumann et al, JCS, 2019). More recently, we have started to address the role of alternative splicing of members of the COPII coat on the secretion of large cargo such as collagen and chylomicrons.