Rab7, a member of the Rab family small G proteins, has been shown to regulate intracellular vesicle traffic to late endosome/lysosome and lysosome biogenesis, but the exact roles of Rab7 are still undetermined. Accumulating evidence suggests that each Rab protein has multiple target proteins that function in the exocytic/endocytic pathway. We have isolated a new Rab7 target protein, Rabring7 (R...

For studies on the lysosome-stabilizing effect of D-glucaric acid derivatives which have been found to have anti-inflammatory effect, the available and soluble enzyme activities of acid phosphatase of rat liver lysosomes were determined. Saliployed as standards. Lysosomes were incubated with drugs under specific conditions which allowed the data on the stabilizing activity of the drugs to be re...

The lysosome has attracted much attention because of its role in the autolysis of cells, and has suggested the importance of introducing the concept of the lysosome into cancer chemotherapy. In the present study acid deoxyribonuclease, (3-glucuronidase and lysozyme in Yoshida ascites tumor cells were proved to be lysosomal enzym~s because of the high latency in their activities and their charac...

Common features of the solid tumor microenvironment, such as acidic extracellular pH and growth factors, are known to induce the redistribution of lysosomes from a perinuclear region to a position near the plasma membrane. Lysosome/plasma membrane juxtaposition facilitates invasion by allowing for the release of lysosomal proteases, including cathepsin B, which contribute to matrix degradation....

The lysosome particles just shown us by Dr. Novikoff and his associates remind me of bodies associated with phagocytosis or pinocytosis, seen in liver parenchymal and endothelial cells, in mesothelial cells and in macrophages. Weatherford in 1932 (1) showed that carbon and colloidal dye particles injected intravenously in frogs are transported across liver endothelial and parenchymal cells and ...

The homeostatic control of the cellular proteome steady-state is dependent either on the 26S proteasome activity or on the lysosome function. The sex hormone 17β-estradiol (E2) controls a plethora of biological functions by binding to the estrogen receptor α (ERα), which is both a nuclear ligand-activated transcription factor and also an extrinsic plasma membrane receptor. Regulation of E2-indu...

Low density lipoprotein cholesteryl [14C]oleate (LDL-[14C]CO) was used as a tool to label lysosomes with cholesteryl [14C]oleate (CO) and to follow subsequently the metabolic processing of oleic acid released by acid lipase. Liberated [14C]oleate was incorporated into glycerolipids, mainly into phosphatidylcholine. Incubations in the presence of various concentrations of exogenously added oleic...

The molecular machinery behind lysosome biogenesis and the maintenance of the perinuclear aggregate of late endocytic structures is not well understood. A likely candidate for being part of this machinery is the small GTPase Rab7, but it is unclear whether this protein is associated with lysosomes or plays any role in the regulation of the perinuclear lysosome compartment. Previously, Rab7 has ...

WASH cleans up after sloppy eaters C arnell et al. have discovered a new job for actin. In social amoebas, actin helps recycle a valuable protein before the cell throws out its garbage. Dictyostelium is not a picky eater. So sometimes the social amoeba gobbles something it can’t digest, such as yeast or the cell walls of certain bacteria, and ends up spitting out its meal. In this process, the ...

It has previously been inferred that the fusion of a macrophage secondary lysosome with a phagosome delivers the entire lysosomal contents uniformly to the phagosome. We found, however, that different fluorescent lysosomal probes can enter phagosomes at remarkably different rates, even though they are initially sequestered together in the same organelles. Thus, sulforhodamine is almost exclusiv...