Amyloid-Like Protein Inclusions in Tobacco Transgenic Plants

Abstract

The formation of insoluble protein deposits in human tissues is linked to the onset of more than 40 different disorders, ranging from dementia to diabetes. In these diseases, the proteins usually self-assemble into ordered β-sheet enriched aggregates known as amyloid fibrils. Here we study the structure of the inclusions formed by maize transglutaminase (TGZ) in the chloroplasts of tobacco transplastomic plants and demonstrate that they have an amyloid-like nature. Together with the evidence of amyloid structures in bacteria and fungi our data argue that amyloid formation is likely a ubiquitous process occurring across the different kingdoms of life. The discovery of amyloid conformations inside inclusions of genetically modified plants might have implications regarding their use for human applications.

Structural Insights into Functional and Pathological Amyloid

“…Recently, amyloid adhesins have been proposed to be abundant in natural biofilms produced by a variety of organisms (76,77). Moreover, bacterial inclusion bodies have been proposed to be composed of amyloid (78), and also there have been amyloid-like inclusions observed in plant chloroplasts (79). As more amyloids and their structures are characterized, it is likely that the concept of amyloid will continue to evolve.…”

Transglutaminase is Involved in the Remodeling of Tobacco Thylakoids

“…Finally, late stages of plant development present alterations in the photosynthetic apparatus, chloroplast ultrastructure, and, particularly, oxidative and antioxidative metabolism pathways are induced (Ortigosa et al 2010). At the same time, the over-expressed TGZ protein, accumulated progressively in chloroplast inclusion bodies (Villar-Piqué et al 2010). These results are discussed in line with chlTGZ involvement in chloroplast functionality.…”

Self-Assembly of Tissue Transglutaminase into Amyloid-Like Fibrils Using Physiological Concentration of Ca2+

“…As we were preparing the present manuscript for submission, a very recent paper reported that the maize transglutaminase can form amyloid-like aggregates in plant cells. 49 Therefore, there is a good possibility that TG2 can form amyloids in a mammalian system.…”