Proteomic Analysis of Plasma Membranes of CyanobacteriumSynechocystissp. Strain PCC 6803 in Response to High pH Stress

Abstract

Cyanobacteria are unique prokaryotes possessing plasma-, outer- and thylakoid membranes. The plasma membrane of a cyanobacterial cell serves as a crucial barrier against its environment and is essential for biogenesis of cyanobacterial photosystems. Previously, we have identified 79 different proteins in the plasma membrane of Synechocystis sp. Strain PCC 6803 based on 2D- and 1D- gels and MALDI-TOF MS. In this work, we have performed a proteomic study screening for high-pH-stress proteins in Synechocystis. 2-D gel profiles of plasma membranes isolated from both control and high pH-treated cells were constructed and compared quantitatively based on different protein staining methods including DIGE analysis. A total of 55 differentially expressed protein spots were identified using MALDI-TOF MS and MALDI-TOF/TOF MS, corresponding to 39 gene products. Twenty-five proteins were enhanced/induced and 14 reduced by high pH. One-third of the enhanced/induced proteins were transport and binding proteins of ABC transporters including 3 phosphate transport proteins. Other proteins include MinD involved in cell division, Cya2 in signaling and proteins involved in photosynthesis and respiration. Furthermore, among these proteins regulated by high pH, eight were found to be hypothetical proteins. Functional significance of the high-pH-stress proteins is discussed integrating current knowledge on cyanobacterial cell physiology.

Novel Insights into the Regulation of LexA in the Cyanobacterium Synechocystis sp. Strain PCC 6803

“…In this work, we report that a LexA::GFP protein fusion is mainly located in the inner region of the cytoplasm, as monitored by GFP fluorescence. These results suggest that the identification of LexA in different membrane fractions reported in various proteomic studies (23,45,54,58) is most likely the result of DNA-contaminated membrane fractions. On the other hand, LexA was found to be evenly distributed on the DNA.…”

“…strain PCC 6803 has been extensively studied over the years, and one aspect that remains to be understood about LexA is connected to its subcellular localization. Several proteomic studies identified LexA, including two-dimensional (2D) gel analyses (11,13,25,41,44,45,54,58), as well as those using more advanced techniques, such as iTRAQ (12). Despite the fact that it is a transcription factor and is predicted to be a cytoplasmic protein, LexA has also been identified in studies specifically focusing on membrane proteins, both in thylakoid (23,45,54) and in plasma membrane (58) fractions.…”

“…In the studies where LexA has been identified in membrane fractions (23,45,54,58), when stated, Synechocystis sp. strain PCC 6803 wild-type cells were grown photoautotrophically in BG11 or AA/8 medium at 30°C, with continuous irradiance at intensities varying between 30 and 60 mol of photons m Ϫ2 s Ϫ1 .…”

Microalgal Systems Biology Through Genome-Scale Metabolic Reconstructions for Industrial Applications

“…After Synechocystis was shown to have three compartments by analysis of signal peptides and N-terminal segments (Rajalahti et al, 2007), Pisareva et al attempted to analyze proteins purified from the plasma membrane, and Wang et al isolated and identified proteins extracted from the outer, plasma, and thylakoid membranes (Pisareva et al, 2007;Wang et al, 2009). The function and regulation of proteins from these membranes were inspected continuously under different stress conditions, such as high pH and copper-and iron-depleted conditions (Castielli et al, 2009;Zhang et al, 2009). Proteins binding to the membrane are thought to have significant roles in photosynthesis and respiration.…”

Differentially Secreted Proteins of Antarctic and Mesophilic Strains ofSynechocystis SalinaandChlorella Vulgarisafter UV-B and Temperature Stress Treatment

“…Pcc 6803 (30) has facilitated proteomic analysis of subcellular compartments (22,26,40,51,55). transcriptomic and proteomic analysis of response to salt stress (15,25), high ph (58), UV-B irradiation (16,27), and heat shock (50,52) resulted in better understanding of cell acclimation in Synechocystis at both the genetic and proteomic level. Singh et al (49) provided the first integrative analysis of transcriptome data sets generated under different stresses and Wegener et al (56) presented the most comprehensive functional and quantitative analysis of the Synechocystis proteome to date.…”