Angew. Chem. Int. Ed. 2012, 51, 6416-6420 Protein Expression, Aggregation, and Triggered Release from Polymersomes as Artificial Cell-like Structures** Chiara Martino, Shin-Hyun Kim, Louise Horsfall, Alireza Abbaspourrad, Susan J. Rosser, Jonathan Cooper,* and David A. Weitz*