Disease relevance of Microbodies

• Response of microbodies in Morris hepatoma 9618A to clofibrate [1].
• Compared to the soluble enzyme from E. coli, the malate synthases from H. polymorpha and both plant species, which are located in the microbodies, have a short carboxy-terminal extension [2].

High impact information on Microbodies

• In clofibrate-treated rats, the tumor cells showed a slight increase in the size of microbodies and in catalase activity; however, the tumor microbodies did not increase in number [1].
• In contrast, in adult clofibrate-treated rats and rats on the day of birth whose mothers received clofibrate during the gestation period, the hepatocytes showed microbodies that were greater in both number and size, and the catalase activity in the liver was definitely elevated [1].
• Matrical inclusions induced by clofibrate in hepatic microbodies of rats fed 2-acetylaminofluorene [3].
• As signal sequences we used the last 22 carboxy-terminal amino acids of glycosomal phosphoglycerate kinase for glycosomes, and the cleavable presequences of yeast cytochrome b2 or cytochrome oxidase subunit IV for mitochondria [4].
• Import of a DHFR hybrid protein into glycosomes in vivo is not inhibited by the folate-analogue aminopterin [4].

Biological context of Microbodies

• One possible explanation is that cytosolic phosphoglycerate kinase creates an ATP-generating shunt in the cytosol, thus preventing full ATP regeneration in the glycosome and ultimately inhibiting the first, ATP-consuming, steps of glycolysis [5].
• Leishmania major expresses a single dihydroxyacetone phosphate acyltransferase localized in the glycosome, important for rapid growth and survival at high cell density and essential for virulence [6].
• Following transcriptional inhibition and during early apoptosis, chromatin retracts from the periphery of PML bodies, coinciding with the formation of new PML-containing structures through fission of supramolecular PML-containing microbodies [7].
• The deduced amino acid sequences of rice and barley BADH both contain a C-terminal tripeptide SKL, a signal known to target preproteins to microbodies [8].
• Biogenesis and metabolic significance of microbodies in urate-utilizing yeasts [9].

Anatomical context of Microbodies

• Regulation of the formation of microbodies in Morris hepatoma 9618A was studied by examination of the response of the organelles to clofibrate [1].
• Trypanosoma brucei contains two isoenzymes for glyceraldehyde-phosphate dehydrogenase (GAPDH); one enzyme resides in a microbody-like organelle, the glycosome, the other one is found in the cytosol [10].
• Fructose bisphosphate aldolase is synthesized on free polysomes and imported into glycosomes within 5 min [11].
• Biochemistry of protozoan microbodies: peroxisomes, alpha-glycerophosphate oxidase bodies, hydrogenosomes [12].
• Cells cultured in glucose-containing medium contain two to five small microbodies, which are identifiable by catalase staining and immunoreactivity with a monoclonal antibody against PMP47, an integral peroxisomal membrane protein [13].

Associations of Microbodies with chemical compounds

• Beginning at about day 3, light-induced activities of enzymes involved in photorespiratory glycolate metabolism accumulate rapidly in microbodies [14].
• Upon addition of aminopterin, a folate analogue that stabilizes the dihydrofolate reductase moiety, import of the fusion protein targeted to glycosomes was not inhibited, although the results of protease protection assays showed that the fusion protein could bind the drug [4].
• The glycosomes were surrounded by a single membrane and contained as phospholipids only phosphatidyl choline and phosphatidyl ethanolamine in a ratio of 2:1 [15].
• Topogenesis of microbody enzymes: a sequence comparison of the genes for the glycosomal (microbody) and cytosolic phosphoglycerate kinases of Trypanosoma brucei [16].
• Thus, interference with glycosome protein import makes glucose toxic to trypanosomes [17].

Gene context of Microbodies

• Both fission and fusion of microbodies with parental PML bodies indicate a loss of structural integrity of the bodies, dependent on the state of the surrounding chromatin [7].
• The proteins encoded by those genes were predicted to have a signal peptide for the secretory pathway, which is consistent with earlier biochemical work that localized allantoinase activity to microbodies and endoplasmic reticulum (Hanks et al., 1981) [18].
• The PEX11 proteins are required for the division of microbodies in trypanosomes, yeast and mammals, and a role of coatomer in this process has been suggested [19].
• Rab39 contains conserved motifs involved in phosphate/guanosine binding and a microbody C-terminal targeting signal [20].
• Peroxin 2 is essential for the import of many proteins into the microbodies of yeasts and mammals [21].

Analytical, diagnostic and therapeutic context of Microbodies

• Immunoblotting of fractions obtained after sucrose density gradient centrifugation of a crude extract indicated that TFP was exclusively localized in glyoxysome-like microbodies [22].
• The epimerase was localized to the glycosomes by immunofluorescence microscopy and subcellular fractionation, suggesting a novel compartmentalization of galactose metabolism in this organism [23].
• These microbodies were isolated successfully by means of sucrose gradient centrifugation from the methanol-grown cells of Kloeckera sp. no [24].
• The bound glycosomes retained their integrity after treatment of tissue en block with uranyl acetate, a procedure that destroyed free glycosomes in the same cell. the coincident distributions of ER and IF and their association with glycosomes suggests a functional relation between there three components [25].
• Sequence analysis of PKX101 revealed two leucine zipper motifs, a putative transmembrane region and a microbody targeting signal at its C-terminal end [26].

References