Die äußere Chloroplastenmembran–kein passives Sieb für Metabolite!

Chloroplasts are essential for energy production and metabolism in plants. Metabolites need to be transported across the two envelope membranes of the chloroplast. In contrast to the inner envelope, we know little about the properties of the outer envelope. We here summarize structural and functional insights on the prototype outer envelope channel OEP21 suggesting that these channels have a distinct level of selectivity, opposing the idea of acting as more simple and passive molecular sieves.