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Full-Text Articles in Life Sciences
Role Of Esterase Gp70 And Its Influence On Growth And Development Of Dictyostelium Discoideum, Aidong Yuan, Catherine P. Chia
Role Of Esterase Gp70 And Its Influence On Growth And Development Of Dictyostelium Discoideum, Aidong Yuan, Catherine P. Chia
Papers in Microbiology
Gp70 is an esterase originally called crystal protein because of its presence in crystalline structures in aggregation-competent Dictyostelium discoideum cells. Although postulated to break down spore coats, the function of gp70 in vivo was incompletely investigated. Our immunolocalization and biochemical studies of vegetative D. discoideum amoebae show that gp70 was recruited to phagosomes and found in lysosomes. Purified gp70 was effective at hydrolyzing naphthyl substrates with acyl chains typical of lipids and lipopolysaccharides, indicating that the gp70 was involved in digesting endocytosed molecules. The activity of purified gp70 was inhibited by reductants that retarded its electrophoretic mobility and verified the …
Cytoskeletal Association Of An Esterase In Dictyostelium Discoideum, Catherine P. Chia, Lothar Bomblies, Kristy K. Taylor
Cytoskeletal Association Of An Esterase In Dictyostelium Discoideum, Catherine P. Chia, Lothar Bomblies, Kristy K. Taylor
Papers in Microbiology
A 70-kDa glycoprotein, gp70, was found enriched in the detergentinsoluble cytoskeletal fraction of axenically grown Dictyostelium discoideum cells. Its N-terminal amino acid sequence identified it as “crystal protein” (L. Bomblies et al., 1990, J. Cell Biol. 110, 669– 679). This finding was corroborated when antibody to crystal protein cross-reacted with gp70 and its deglycosylated form. The postulated esterase activity of gp70/crystal protein was verified through comparative enzyme assays of extracts derived from cells that either overexpressed or lacked gp70. Gp70 cosedimented with cytoskeletons on sucrose gradients, suggesting an interaction with the cytoskeleton. Coisolation of gp70 with detergent-extracted cells, observed by …
Phagosomal Proteins Of Dictyostelium Discoideum, Betsy L. Rezabek, Juan M. Rodriguez-Paris, James A. Cardelli, Catherine P. Chia
Phagosomal Proteins Of Dictyostelium Discoideum, Betsy L. Rezabek, Juan M. Rodriguez-Paris, James A. Cardelli, Catherine P. Chia
Papers in Microbiology
In recognizing food particles, Dictyostelium cell-surface molecules initiate cytoskeletal rearrangements that result in phagosome formation. After feeding D. discoideum cells latex beads, early phagosomes were isolated on sucrose step gradients. Protein analyses of these vesicles showed that they contained glycoproteins and surface-labeled species corresponding to integral plasma membrane proteins. Cytoskeletal proteins also were associated with phagosomes, including myosin II, actin and a 30 kDa-actin bundling protein. As seen by the acridine orange fluorescence of vesicles containing bacteria, phagosomes were acidified rapidly by a vacuolar H+-ATPase that was detected by immunoblotting. Except for the loss of cytoskeletal proteins, few other changes …