Recently, Professor Gao Hongbo’s research team conducted an in-depth study on the mechanism of FtsZ1, a key protein in chloroplast division, discovering a new class of membrane binding motifs which enriches understanding of protein-biofilm binding and make contribution to the regulation in other species and other cellular physiological processes.
As an important biological process in plant cells, chloroplast division plays a significant role in the normal growth and reproduction of plants through keeping a set number of chloroplasts in the cell. Therefore, the study of the molecular mechanism of chloroplast division becomes an important direction in the field of botany research.
FtsZ is the ancestor of cytoskeleton microtubule tubulin. As the skeleton protein of the chloroplast division protein complex in chloroplasts, FtsZ not only plays a key role in the assembly of chloroplast fission ring, but also hydrolyzes GTP to promote chloroplast division. FtsZ ring is composed of FtsZ proteins, but plants contain two FtsZ subfamilies, FtsZ1 and FtsZ2.
In the latest study, Prof. Hongbo Gao’s team identified a special conserved motif at the C-terminal of FtsZ1 through bioinformatics analysis, and named it Z1C. Mutant without this motif is abnormal in the chloroplast division with the chloroplasts heterogeneous in size and hindered in division. Immunofluorescence staining showed that the Z-ring in chloroplast of the mutant was filamentous and could not gather at the cleavage site. Through further cell biology, biochemistry and chemical analysis, it is revealed that the Z1C motif is a novel membrane-binding motif. Different from the traditional amphiphilic motif, it is beta-strand. The motif itself is weak in membrane-binding activity, but polymer containing the motif is relatively strong in membrane-binding activity. The special membrane-binding motif is conducive to the dynamic regulation of Z-ring and complex formation of chloroplast division.
Working model of the structure and activity of the C-terminus of FtsZ1. The Z1C motif helps the FtsZ2/FtsZ1 copolymer bind to the chloroplast inner envelope.
The research results “A novel amphiphilic motif at the C-terminus of FtsZ1 facilitates chloroplast division” was published in The Plant Cell (impact factor: 11.3). The first author of the paper is Liu Xiaomin, a doctoral candidate at the College of Biological Sciences and Biotechnology, and the corresponding author is Prof. Gao Hongbo. An Jinjie, Wang Lulu and other doctoral candidates were also participated in the research. This research work was supported by Peking University and Beijing University of Chemical Technologygrants, and the financial support for this work was provided by the National Natural Science Foundation of China.
Paper link: https://academic.oup.com/plcell/advance-article/doi/10.1093/plcell/koab272/6424909