bioRxiv Science⌕ Search

Biology subjects

Dahlgren, K. K.

Publications and source records attributed to Dahlgren, K. K..

2 recordsLinked to original sources

Kinetics and targeting of Vipp1 aggregation in cyanobacteria

The kinetics of regulation of vesicle-inducing protein in plastids (Vipp1), an essential protein in all oxygenic phototrophs, are not completely understood. Vipp1 is responsible for both membrane maintenance and damage repair processes, aggregating at sites of damage (proton leakage) or physical strain (responding to presence of anionic lipids). Herein we spatiotemporally resolve exchange between inactive cytoplasmic Vipp1 and these two functionalities. We demonstrate that Vipp1 can be aggregated to a specific site in the thylakoid membrane by laser damage, but this behavior appears to be mediated by a rapidly resolved secondary process, as cytoplasmic Vipp1 is rendered unresponsive to nearby damage on a time scale three orders of magnitude faster than the aggregation process itself. One Sentence SummaryVipp1 aggregation to points on the thylakoid is induced in response to specific damage and repair kinetics are observed.

biochemistry↗

Proximity-based proteomics reveals the thylakoid lumen proteome in the cyanobacterium Synechococcus sp. PCC 7002

Cyanobacteria possess unique intracellular organization. Many proteomic studies have examined different features of cyanobacteria to learn about the structure-function relationships between the intracellular structures of cyanobacteria and their roles in cells. While these studies have made great progress in understanding cyanobacterial physiology, the previous fractionation methods used to purify cellular structures have limitations; specifically, certain regions of cells cannot be purified with existing fractionation methods. Proximity-based proteomics techniques were developed to overcome the limitations of biochemical fractionation for proteomics. Proximity-based proteomics relies on spatiotemporal protein labeling followed by mass spectrometry of the labeled proteins to determine the proteome of the region of interest. We have performed proximity-based proteomics in the cyanobacterium Synechococcus sp. PCC 7002 with the APEX2 enzyme, an engineered ascorbate peroxidase. We determined the proteome of the thylakoid lumen, a region of the cell that has remained challenging to study with existing methods, using a PsbU-APEX2 gene fusion. This study demonstrates the power of APEX2 as a tool to study the cell biology of intracellular features of cyanobacteria with enhanced spatiotemporal resolution.

biochemistry↗