Acidocalcisomes - Conserved from bacteria to man

Department of Cellular Biology and Center for Tropical and Global Emerging Diseases, University of Georgia, Athens, Georgia 30602, USA.
Nature Reviews Microbiology (Impact Factor: 23.57). 04/2005; 3(3):251-61. DOI: 10.1038/nrmicro1097
Source: PubMed

ABSTRACT Recent work has shown that acidocalcisomes, which are electron-dense acidic organelles rich in calcium and polyphosphate, are the only organelles that have been conserved during evolution from prokaryotes to eukaryotes. Acidocalcisomes were first described in trypanosomatids and have been characterized in most detail in these species. Acidocalcisomes have been linked with several functions, including storage of cations and phosphorus, polyphosphate metabolism, calcium homeostasis, maintenance of intracellular pH homeostasis and osmoregulation. Here, we review acidocalcisome ultrastructure, composition and function in different trypanosomatids and other organisms.

28 Reads
  • Source
    • "Unfortunately through the years many studies have not been and polyphosphate (poly P) [55]. In eukaryotic microbes, acidocalcisomes function in P metabolism, Ca 2+ homeostasis, maintenance of intracellular pH, and osmoregulation [55] [56]. Prokaryotic acidocalcisomes are very similar to their eukaryotic counterparts containing the transporters H + -ATPase and the vacuolar proton translocating pyrophosphatase responsible for their acidification [53]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: With the continued increase of genomic information and computational analyses during the recent years, the number of newly discovered calcium binding proteins (CaBPs) in prokaryotic organisms has increased dramatically. These proteins contain sequences that closely resemble a variety of eukaryotic calcium (Ca2+) binding motifs including the canonical and pseudo EF-hand motifs, Ca2+-binding ß-roll, Greek key motif and a novel putative Ca2+-binding domain, called the Big domain. Prokaryotic CaBPs have been implicated in diverse cellular activities such as division, development, motility, homeostasis, stress response, secretion, transport, signaling, and host-pathogen interactions. However, the majority of these proteins are hypothetical, and only few of them have been studied functionally. The finding of many diverse CaBPs in prokaryotic genomes opens an exciting area of research to explore and define the role of Ca2+ in organisms other than eukaryotes. This review presents the most recent developments in the field of CaBPs and novel advancements in the role of Ca2+ in prokaryotes.
    Cell Calcium 12/2014; 57(3). DOI:10.1016/j.ceca.2014.12.006 · 3.51 Impact Factor
  • Source
    • "Organisms utilize polyphosphate to regenerate nucleotide triphosphates (Kuroda et al. 1997); therefore, polyphosphate storage granules are regarded as energy storage granules. In eukaryotes, polyphosphate storage granules are found in membrane bound organelles and a similar architecture has been suggested in bacteria (Docampo et al. 2005). Other types of membrane-encapsulated particles have been clearly visualized by ECT (Komeili 2006); however, in C. jejuni the polyphosphate storage granules are not enclosed by membranes . "
    [Show abstract] [Hide abstract]
    ABSTRACT: Campylobacter jejuni is one of the most successful food-borne human pathogens. Here we use electron cryotomography to explore the ultrastructure of C. jejuni cells in logarithmically growing cultures. This provides the first look at this pathogen in a near-native state at macromolecular resolution (~5 nm). We find a surprisingly complex polar architecture that includes ribosome exclusion zones, polyphosphate storage granules, extensive collar-shaped chemoreceptor arrays, and elaborate flagellar motors.
    MicrobiologyOpen 10/2014; 3(5). DOI:10.1002/mbo3.200 · 2.21 Impact Factor
  • Source
    • "In certain eukaryotes, the volutin granule is a membrane-bound storage organelle for calcium as well as polyphosphate. This organelle was found to be acidic; this type of organelle is now called the acidocalcisome [6]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The budding yeast Saccharomyces cerevisiae serves as an effective model organism for many cel-lular pathways including phosphate transport, accumulation, and storage. In S. cerevisiae, phos-phate is actively transported across the plasma membrane via several phosphate carriers and is then transported into the acidic vacuole (roughly equivalent to the mammalian lysosome with de-gradative functions but with additional storage functions, such as calcium) where it is synthesized into volutin, a storage form of polyphosphate, found in many organisms. We have been studying volutin granule formation in wild type cells to determine the physiological requirements for for-mation and in mutants to determine the pathway by which the volutin biosynthetic proteins are transported to the vacuole. Undertaking an analysis of volutin formation in yeast vacuoles by blocking vacuole function with pharmacological agents, such as ionomycin and CCCP, we see that vacuole pH as well as vacuolar calcium seems critical for volutin formation. Different blocks in vacuolar protein sorting have differential effects on volutin granule accumulation, with volutin granule formation seen in all mutant strains thus far tested, except for vps33, a mutant cell strain lacking all vacuolar structure. Our data are consistent with pleiotrophic effects of vacuolar physi-ological function blocks leading to a decrease in volutin formation.
    Advances in Microbiology 06/2014; 04(08). DOI:10.4236/aim.2014.48051
Show more


28 Reads
Available from