Autophagy is a lysosomal degradation pathway for cytoplasmic material, which is activated during stress conditions such as amino acid starvation or viral infection. Yeast mutants defective in autophagy do not survive starvation. Mammalian cells use autophagy during short periods of starvation...

Lysosomes are membrane-surrounded organelles which are present virtually in all animal cells. They function to degrade both intra- and extracellular macromolecules to low molecular components that are transported to the cytoplasm for reutilization in the biosynthetic pathways of the cell. Up...

Neuronal ceroid-lipofuscinoses (NCLs, also referred to as Batten’s disease) are inherited lysosomal storage diseases characterized by progressive neurodegeneration and premature death. As a group, the NCLs compose the most common reason for children’s progressive encephalopathy, and their...

Ca2+-regulated exocytosis was proposed to mediate plasma membrane repair , but until recently the nature of the vesicles involved was unknown. Recent work from our labo ratory identified lysosomes as the intracellular organelles responsible for this process. Ca2+ triggers the exocytosis of...

Many lysosomal and nonlysosomal pathways degrade intracellular proteins and this variety allows all cell proteins to be proteolysed at various speeds in response to different stimuli. Lysosomes, which are present in almost all eukaryotic cells, are major sites of intracellular proteolysis....

As reflected in this monograph, a lot of knowledge about the lysosomal compartment has been acquired since the discovery of the organelle by de Duve and others in the 1950s. Nevertheless, a lot of questions are still open, and some of them can be addressed using screening techniques. Among...

Lysosomes contain the enzymatic machinery to digest a host of organic substances. This degrading activity occurs primarily inside the living cell where the lysosomes reside. Yet, some cells use lysosomal enzymes in the extracellular space to digest proteins in their direct vicinity. Secretion...

The lysosomal limiting membrane has multiple functions including acidification of the lysosomal matrix, sequestration of lysosomal enzymes, mediation of fusion events beween lysosomes and other organelles, and transport of degradation products to the cytoplasm. Lysosomal membrane proteins are...

Lysosomal proteases belong to the aspartic, cysteine, or serine proteinase families of hydrolytic enzymes. They are expressed ubiquitously, and in a tissue- or cell type-specific manner. Although we still call them lysosomal proteases, the enzymes are usually detected within all vesicles of...

The lysosome is the cell‘s main digestive compartment to which all sorts of macromol ecules are delivered for degradation. The structure of the lysosome is variable and de pends on the cell type and the actual conditions. In terms of function and cytochemistry, the lysosome is identified by...

The lysosomal storage disorders (LSD) are a group of about 50 diseases that are characterised by an accumulation of waste products in the lysosomes, resulting in the formation of large intracellular vacuoles (Fig. 1). Many of the diseases that we now know as lysosomal storage disorders, were...

Human papillomaviruses (HPVs) are a large group of infectious agents that induce various lesions of skin and mucosae. The carcinogenic role of HPV types 16 and 18, mediated by inactivation of the tumor suppressor proteins p53 and pRb by the viral oncoproteins E6 and E7, is established for...

Lysosomal membrane proteins and soluble lysosomal proteins are transported from the trans-Golgi network (TGN) to endosomes and lysosomes via coated-vesicles, which bud from the donor compartment and are transported to and fuse with the proper acceptor compartment. The proteins forming the...

More than 50 acid hydrolases involved in the ordered lysosomal degradation of a variety of proteins, lipids, carbohydrates, and nucleic acids have been identified. The hydrolases are enclosed by a membrane containing a set of highly glycosylated lysosomal membrane proteins. Lysosomal enzymes...