Skeletons in the Closet: How Do Chloroplasts Stay in Shape?

Breakthroughs in microscopy technology provide new insights into cell biology. Early microscopes allowed Robert Hooke to see cells. Improved staining techniques enabled Camillo Golgi to see the apparatus that bears his name, and Robert Feulgen to visualize DNA in chromosomes. Similarly, EM allowed Keith Porter to visualize the endomembrane system. More recently, transgenic technology using fluorescent reporter proteins has enabled us to visualize cryptic or ephemeral processes and structures in living cells. The latest revelation with this technology is in chloroplast biology. On page 945 of this issue, Kiessling et al. show that fusion of green fluorescent protein (GFP) with the FtsZ (filament temperature sensitive Z) protein targeted to chloroplasts of the moss Physcomitrella reveals a network of fibers within the chloroplast (Fig. 1). They dub this network the plastoskeleton, since it is reminiscent of cytoskeletons. Plant...