The Lattice-Like Structure Observed by Vippl-GFP in Arabidopsis Chloroplasts

摘要

Vipp1 (vesicle inducing protein in plastids 1) is proposed to play a role in thylakoid biogenesis. It is closely related to PspA (phage shock protein A), a bacterial protein that is induced under stress conditions. Despite its discovery a decade ago and extensive analysis in cyanobacteria, green algae and higher plants, the precise role of Vippl in the process of chloroplast development remains unclear. In this research, we expressed Vippl C-terminally fused to GFP (Vippl-GFP) in Arabidopsis and found that Vipp1 is able to assemble into rod-shaped supercomplexes. Vippl-GFP can rescue heterotrophic growth of a vippl knock-down mutant, suggesting that it complements Vippl function. Interestingly, VipplGFP rods always appeared to cross with each other to form a lattice-like structure, which is similar to a scaffold structure formed by PspA in Escherichia coli. Based on these results, we infer that Vippl is involved in not only thylakoid biogenesis but chloroplast envelope integrity.