Article

Localization of acidic phospholipid cardiolipin and DnaA in mycobacteria.

Biomedical Research, The University of Texas Health Science Center, 11937 US Hwy @ 271, Tyler, TX 75708-3154, United States.
Tuberculosis (Edinburgh, Scotland) (Impact Factor: 3.5). 12/2011; 91 Suppl 1:S150-5. DOI: 10.1016/j.tube.2011.10.025
Source: PubMed

ABSTRACT Acidic phospholipids such as cardiolipin (CL) have been shown to modulate Mycobacterium tuberculosis (Mtb) DnaA interactions with ATP. In the present study, using nonyl acridine orange fluorescent dye we localized CL-enriched regions to midcell septa and poles of actively dividing cells. We also found that CL-enriched regions were not visualized in cells defective for septa formation as a consequence of altered FtsZ levels. Using Mtb cultures synchronized for DNA replication we show that CL localization could be used as a marker for cell division and cell cycle progression. Finally, we show that the localization pattern of the DnaA-green fluorescent fusion protein is similar to CL. Our results suggest that DnaA colocalizes with CL during cell cycle progression.

Download full-text

Full-text

Available from: Malini Rajagopalan, Dec 19, 2014
0 Followers
 · 
193 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: At all levels of Life, systems evolve on the 'scales of equilibria'. At the level of bacteria, the individual cell must favor one of two opposing strategies and either take risks to grow or avoid risks to survive. It has been proposed in the Dualism hypothesis that the growth and survival strategies depend on non-equilibrium and equilibrium hyperstructures, respectively. It has been further proposed that the cell cycle itself is the way cells manage to balance the ratios of these types of hyperstructure so as to achieve the compromise solution of living on the two scales. Here, we attempt to re-interpret a major event, the initiation of chromosome replication in Escherichia coli, in the light of scales of equilibria. This entails thinking in terms of hyperstructures as responsible for intensity sensing and quantity sensing and how this sensing might help explain the role of the DnaA protein in initiation of replication. We outline experiments and an automaton approach to the cell cycle that should test and refine the scales concept.
    12/2012; 2(4):286-312. DOI:10.3390/life2040286
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Understanding the mechanism that controls space-time coordination of elongation and division of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is critical for fighting the tubercle bacillus. Most of the numerous enzymes involved in the synthesis of Mycolic acid - Arabinogalactan-Peptidoglycan complex (MAPc) in the cell wall are essential in vivo. Using a dynamic approach, we localized Mtb enzymes belonging to the fatty acid synthase-II (FAS-II) complexes and involved in mycolic acid (MA) biosynthesis in a mycobacterial model of Mtb: M. smegmatis. Results also showed that the MA transporter MmpL3 was present in the mycobacterial envelope and was specifically and dynamically accumulated at the poles and septa during bacterial growth. This localization was due to its C-terminal domain. Moreover, the FAS-II enzymes were co-localized at the poles and septum with Wag31, the protein responsible for the polar localization of mycobacterial peptidoglycan biosynthesis. The dynamic localization of FAS-II and of the MA transporter with Wag31, at the old-growing poles and at the septum suggests that the main components of the mycomembrane may potentially be synthesized at these precise foci. This finding highlights a major difference between mycobacteria and other rod-shaped bacteria studied to date. Based on the already known polar activities of envelope biosynthesis in mycobacteria, we propose the existence of complex polar machinery devoted to the biogenesis of the entire envelope. As a result, the mycobacterial pole would represent the Achilles' heel of the bacillus at all its growing stages.
    PLoS ONE 05/2014; 9(5):e97148. DOI:10.1371/journal.pone.0097148 · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An ancient anionic phospholipid, cardiolipin, ubiquitously present in prokaryotic and eukaryotic membranes, is essential for several structural and functional purposes. The emerging role of cardiolipins in signaling has become the focus of many studies. In this work, we describe two major pathways through which mitochondrial cardiolipins may fulfill the signaling functions via utilization of their: i) asymmetric distribution across membranes and translocations leading to the surface externalization, and ii) ability to undergo oxidation reactions to yield the signature products recognizable by the executionary machinery of cells. We present a concept that cardiolipins and their oxidation/hydrolysis products constitute a rich communication language utilized by mitochondria of eukaryotic cells for diversified regulation of cell physiology and metabolism as well as for inter-cellular interactions.
    Antioxidants and Redox Signaling 01/2015; 22(18). DOI:10.1089/ars.2014.6219 · 7.67 Impact Factor
Show more