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The Role Of Gtp Binding And Hydrolysis At The Attoc159 Preprotein Receptor During Protein Import Into Chloroplasts, Danny Schnell, F. Wang, B. Agne, F. Kessler
The Role Of Gtp Binding And Hydrolysis At The Attoc159 Preprotein Receptor During Protein Import Into Chloroplasts, Danny Schnell, F. Wang, B. Agne, F. Kessler
Danny Schnell
The majority of nucleus-encoded chloroplast proteins are targeted to the organelle by direct binding to two membrane-bound GTPase receptors, Toc34 and Toc159. The GTPase activities of the receptors are implicated in two key import activities, preprotein binding and driving membrane translocation, but their precise functions have not been defined. We use a combination of in vivo and in vitro approaches to study the role of the Toc159 receptor in the import reaction. We show that atToc159-A864R, a receptor with reduced GTPase activity, can fully complement a lethal insertion mutation in the ATTOC159 gene. Surprisingly, the atToc159-A864R receptor increases the rate …
Arabidopsis Tic40 Expression In Tobacco Chloroplasts Results In Massive Proliferation Of The Inner Envelope Membrane And Upregulation Of Associated Proteins, Danny Schnell, N. D. Singh, M. Li, S. B. Lee, H Daniell
Arabidopsis Tic40 Expression In Tobacco Chloroplasts Results In Massive Proliferation Of The Inner Envelope Membrane And Upregulation Of Associated Proteins, Danny Schnell, N. D. Singh, M. Li, S. B. Lee, H Daniell
Danny Schnell
The chloroplast inner envelope membrane (IM) plays essential roles in lipid synthesis, metabolite transport, and cellular signaling in plants. We have targeted a model nucleus-encoded IM protein from Arabidopsis thaliana, pre-Tic40-His, by relocating its expression from the nucleus to the chloroplast genome. Pre-Tic40-His was properly targeted, processed, and inserted. It attained correct topology and was folded and assembled into a TIC complex, where it accounted for up to 15% of the total chloroplast protein. These results confirm the existence of a novel pathway for protein targeting to the IM. Tic40-His overexpression resulted in a massive proliferation of the IM (up …