Dr. Bettina Bölter
Department für BiologieI, Botanik
AG Soll
Menzingerstr. 67
80638 München

The vast majority of chloroplast proteins is translated in the cytosol and posttranslationally imported into the organelle. Transport is mediated by two translocation machineries in the outer and the inner envelope membrane, respectively. Whereas the translocation process across the outer envelope through the Toc complex (translocon at the outer envelope of chloroplasts) has been characterized to some detail, less is known about the function of the Tic complex (translocon at the inner envelope of chloroplasts). Seven components have been identified so far: Tic110 forms the translocation channel; Tic40 has been assorted to chaperone recruitment; Tic62, Tic55 and Tic32 show features indicative of redox regulated components. Tic22 forms an intermembrane complex together with Toc64 and Toc12. For Tic20 no function has been shown yet though it is discussed as part of the translocation pore.