Organelle

Department of Medical Biochemistry and Biology, University of Bari, Italy; 2Department of Zoology, Laboratory of Histology and Comparative Anatomy, University of Bari, Italy; 3Center for the Study of Mitochondria and Energy Metabolism (CNR) Bari, Italy Mitochondrial bioenergetic impairment has been found in the organelles isolated from rat liver during the prereplicative phase of liver regeneration.

9p system191 01-06-2013 36 4   Download

Cellular manifestations of aging are most pronounced in postmitotic cells, such as neurons and cardiac myocytes. Alterations of these cells, which are responsible for essential functions of brain and heart, are particularly important contributors to the overall aging process. Mitochondria and lysosomes of postmitotic cells suffer the most remarkable age-related alterations of all cellular organelles.

7p research12 01-06-2013 41 5   Download

The vacuolar H + -ATPase (V-ATPase) is a multimeric enzyme complex that acidi®es organelles of the vacuolar system in eukaryotic cells. Proteins that interact with the V-ATPase may play an important role in controlling the intracellular localization and activity of the proton pump. The neuroendocrine-enriched V-ATPase accessory subunit Ac45 may represent such a protein as it has been shown to interactwith themembrane sector of theV-ATPase inonlya subset of organelles.

10p research12 23-04-2013 41 3   Download

ATP-regenerating enzymes may have an important role in maintaining ATP levels in mitochondria-like kinetoplast organelle and glycosomes in parasitic protozoa. Adenylate kinase (AK) (ATP:AMP phosphotransferase) catalyses the reversible transfer of thec-phosphate group from ATP to AMP, releasing twomolecules ofADP. This study describes cloningand functional characterizationof the gene encoding AK2fromagenomic libraryofLeishmaniadonovaniandalso its expression in leishmania promastigote cultures.

9p tumor12 20-04-2013 39 3   Download

Tip growth is a specialized type of polar growth where new cell wall is deposited in a localized region of the cell, the growing tip. These cells show a characteristic zonation, with a high accumulationof secretory vesicles containing cell wall components at the tip, followed by an organelle-enriched zone.MsPG3is a Medicago sativapolygalacturonase gene isolated in our laboratory, specifically expressed during the interaction of this plant with its symbiotic partner Sinorhiz-obium melilotiand which might participate in tip growth processes during symbiosis....

9p tumor12 20-04-2013 41 3   Download

It has been shown previously in various organisms that the peroxin PEX14 is a component of a docking complex at the peroxisomalmembrane,where it is involved in the import of matrix proteins into the organelle after their synthesis in the cytosol and recognition by a receptor. Here we present a characterization of theTrypanosoma bruceihomologue of PEX14. It is shown that the protein is associated with gly-cosomes,the peroxisome-like organelles of trypanosomatids in which most glycolytic enzymes are compartmentalized....

9p fptmusic 16-04-2013 47 2   Download

The abundance and size of cellular organelles vary depending on the cell type and metabolic needs. Peroxisomes constitute a class of cellular organ-elles renowned for their ability to adapt to cellular and environmental conditions. Together with transcriptional regulators, two groups of per-oxisomal proteins have a pronounced influence on peroxisome size and abundance.

13p fptmusic 12-04-2013 45 1   Download

Assembly of the components of the thylakoidDpH-dependent/Tat protein transport machinery was analyzed in vitro. Upon incubation with intact chloroplasts, precur-sors to all three components, Hcf106, cpTatC and Tha4, were imported into the organelle and assembled into char-acteristic endogenous complexes. In particular, all of the imported cpTatC and approximately two-thirds of the imported Hcf106functionally assembled into 700 kDa complexes capable of binding Tat pathway precursor pro-teins.

12p fptmusic 12-04-2013 47 3   Download

The development of targeted probes (based on the molecular engineering of luminescent or fluorescent proteins) has allowed the specific measure-ment of [Ca 2+ ] in intracellular organelles or cytoplasmic subdomains. This approach gave novel information on different aspects of cellular Ca 2+ homeostasis. Regarding mitochondria, it was possible to demonstrate that, upon physiological stimulation of cells, Ca 2+ is rapidly accumulated in the matrix.

10p fptmusic 11-04-2013 41 2   Download

Genetic and proteomic approaches have led to the identification of 32 pro-teins, collectively called peroxins, which are required for the biogenesis of peroxisomes. Some are responsible for the division and inheritance of per-oxisomes; however, most peroxins have been implicated in the topogenesis of peroxisomal proteins. Peroxisomal membrane and matrix proteins are synthesized on free ribosomes in the cytosol and are imported post-trans-lationally into pre-existing organelles (Lazarow PB & Fujiki Y (1985) Annu Rev Cell Biol1, 489–530 [1])....

11p awards 06-04-2013 49 4   Download

Higher plant chloroplasts possess at least four different pathways for pro-tein translocation across and protein integration into the thylakoid mem-branes. It is of interest with respect to plastid evolution, which pathways have been retained as a relic from the cyanobacterial ancestor (‘conserva-tive sorting’), which ones have been kept but modified, and which ones were developed at the organelle stage, i.e. are eukaryotic achievements as (largely) the Toc and Tic translocons for envelope import of cytosolic pre-cursor proteins. ...

12p awards 05-04-2013 36 4   Download

Many organelle enzymes coded for by nuclear genes have N-terminal sequences, which directs them into the organelle (precursor) and are removed upon import (mature). The experiments described below charac-terize the differences between the precursor and mature forms of water-melon glyoxysomal malate dehydrogenase. Using recombinant protein methods, the precursor (p-gMDH) and mature (gMDH) forms were puri-fied to homogeneity using Ni 2+ –NTA affinity chromatography.

0p awards 05-04-2013 49 2   Download

The nematocyst capsules of the cnidarians are specialized explosive organelles that withstand high osmotic pressures of
15 MPa (150 bar). A tight disulfide network involving cysteine-rich capsule wall proteins, like minicollagens and nematocyst outer wall antigen, characterizes their molecular composition.

8p inspiron33 25-03-2013 43 3   Download

We have investigated the direct effect of arachidonic acid on cholesterol transport in intact cells or isolated mitochondria from steroidogenic cells and the effect of cyclic-AMP on the specific release of this fatty acid inside the mitochondria. We show for the first time that cyclic-AMP can regulate the release of arachidonic acid in a specialized compartment of MA-10 Leydig cells, e.g.

11p inspiron33 23-03-2013 35 5   Download

PEX1 is a type II AAA-ATPase that is indispensable for biogenesis and maintenance of the peroxisome, an organelle responsible for the primary metabolism of lipids, such asb-oxidation and lipid biosynthesis. Recently, we demonstrated a striking structural similarity between its N-terminal domain and those of other membrane-related AAA-ATPases, such as valo-sin-containing protein (p97).

13p inspiron33 23-03-2013 42 4   Download

Aconitases are iron–sulfur hydrolyases catalysing the interconversion of cit-rate and isocitrate in a wide variety of organisms. Eukaryotic aconitases have been assigned additional roles, as in the case of the metazoan dual activity cytosolic aconitase–iron regulatory protein 1 (IRP1). This human protein was produced in yeast mitochondria to probe IRP1 folding in this organelle where iron–sulfur synthesis originates.

10p galaxyss3 21-03-2013 47 5   Download

Cathepsin E (CatE) and D (CatD) are the major aspartic proteinases in the endolysosomal pathway. They have similar specificity and therefore it is difficult to distinguish between them, as known substrates are not exclu-sively specific for one or the other.

12p galaxyss3 19-03-2013 32 2   Download

The eye lens is composed of fiber cells that differentiate from epithelial cells on its anterior surface. In concert with this differentiation, a set of proteins essential for lens function is synthesized, and the cellular organelles are degraded. DNase II-like acid DNase, also called DNase IIb, is specifically expressed in the lens, and degrades the DNA in the lens fiber cells.

10p galaxyss3 19-03-2013 46 3   Download

The eye lens is composed of fiber cells that differentiate from epithelial cells on its anterior surface. In concert with this differentiation, a set of proteins essential for lens function is synthesized, and the cellular organelles are degraded.

16p galaxyss3 19-03-2013 40 4   Download

Autophagy is a nonspecific bulk degradation pathway for long-lived cyto-plasmic proteins, protein complexes, or damaged organelles. This process is also a major degradation pathway for many aggregate-prone, disease-cau-sing proteins associated with neurodegenerative disorders, such as mutant huntingtin in Huntington’s disease. I

8p galaxyss3 07-03-2013 47 5   Download