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"Directed evolution" is the process by which scientists produce tailor-made proteins for cell biology, physiology and biomedicine in the laboratory. Based on this method, Max Planck researchers from Martinsried have now developed ...

Changes in cellular degradation hubs can lead to cancer

Cancer cells grow and divide in an uncontrolled manner. A new study from Uppsala University now shows how alterations in a cell's degradation hubs, called lysosomes, can cause abnormal cell growth. The results are published ...

Why cells need acidic lysosomes

Just like the body contains lungs, liver, and lymph nodes, so does each of the body's cells contain tiny specialized organs. Perhaps most peculiar among them are lysosomes—bubble-like sacks that act as part recycling bin, ...

Biological risk potential of nanoparticles studied

Carbon nanoparticles are a promising tool for biomedical applications, for example, for targeted transportation of biologically active compounds into cells. A team of researchers from the Physics, Medicine and Chemistry departments ...

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Lysosome

Lysosomes are cellular organelles that contain acid hydrolase enzymes to break down waste materials and cellular debris. They are found in animal cells, while in yeast and plants the same roles are performed by lytic vacuoles. Lysosomes digest excess or worn-out organelles, food particles, and engulf viruses or bacteria. The membrane around a lysosome allows the digestive enzymes to work at the 4.5 pH they require. Lysosomes fuse with vacuoles and dispense their enzymes into the vacuoles, digesting their contents. They are created by the addition of hydrolytic enzymes to early endosomes from the Golgi apparatus. The name lysosome derives from the Greek words lysis, to separate, and soma, body. They are frequently nicknamed "suicide-bags" or "suicide-sacs" by cell biologists due to their role in autolysis. Lysosomes were discovered by the Belgian cytologist Christian de Duve in the 1960s.

The size of lysosomes varies from 0.1–1.2 μm. At pH 4.8, the interior of the lysosomes is acidic compared to the slightly alkaline cytosol (pH 7.2). The lysosome maintains this pH differential by pumping protons (H+ ions) from the cytosol across the membrane via proton pumps and chloride ion channels. The lysosomal membrane protects the cytosol, and therefore the rest of the cell, from the degradative enzymes within the lysosome. The cell is additionally protected from any lysosomal acid hydrolases that drain into the cytosol, as these enzymes aren't pH-sensitive and function as well in the alkaline environment of the cytosol.

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