Lysosome functions

Lange PF, Wartosch L, Jentsch TJ et al (2006) C1C-7 requires Ostml as a p-subunit to support bone resorption and lysosomal function. Nature 440 220-223... 

Modified from Olkonnen VM, Ikonen E Genetic defects of intra-cellular-membrane transport. N Eng J Med 2000343 1095. Certain related conditions not listed here are also described in this publication. l-cell disease is described in Chapter 47. The majority of the disorders listed above affect lysosomal function readers should consult a textbook of medicine for information on the clinical manifestations of these conditions. 

Some of these are listed in Table 46-9 the majority affect lysosomal function. A number of other mutations affecting intracellular protein transport have been reported but are not included here. 

Lange, P.F., Wartosch, L., Jentsch, T.J., and Fnhrmann, J.C. (2006) ClC-7 Requires Ostml as a p Subunit to Support Bone Resorption and Lysosomal Function. Nature 440, 220-223. 

Poole, B., Ohkuma, S., and Warburton, M. (1978). Some aspects of the intracellular breakdown of exogenous and endogenous proteins. In Segal H.L. and Doyle D.J., eds. Protein Turnover and Lysosome Function. Academic Press, New York, NY USA. pp. 43-58. 

Several disorders that lead to Impaired lysosome function Include the mucolipidoses l-cell disease and pseudo-Hurler polydystrophy. 

Lysosome function is consequently less impaired in ML-III patients than in ML-II patients. 

Wolfe JH, Schuchman EH, Stramm LE, et al. Restoration of normal lysosomal function in mucopolysaccharidosis type VII by retroviral vector-mediated gene transfer. Proc Natl Acad Sci U.S.A. 87 2877-2881,1990. 

Figure 29.10. Postulated pathways of aminoglycoside-induced cellular injury. On the left, aminoglycoside (AG) enters the cell by pinocytosis and endocytosis, subsequently fusing with a primary lysosome (L). Aminoglycosides may interfere with normal lysosomal function, forming myeloid bodies (center). Additionally, aminoglycosides may destabilize lysosomes, leading to release of intralysosomal enzymes (lower left). Intracellular aminoglycosides may produce direct injury to intracellular organelles such as mitochondria. (Adapted from G.J. Kaloyanides and E. Pastoriza-Munoz, Kidney Int. 18, 571-582,1980.)...

Lysosomes are in effect a cellular waste-bin, and play an important role in the turnover and degradation of cytoplasmic organelles and phago-cytosed particles. They facilitate receptor-mediated endocytosis of many macromolecules from the cell membrane. Lysosomes carry hydrolases that degrade nucleotides, proteins, lipids and phospholipids they also remove carbohydrate, sulphate, or phosphate groups from molecules. Lysosomes store iron, either as soluble ferritin or as products of ferritin degradation, such as haemosiderin. Abnormalities associated with lysosomal function cause a variety of storage disorders such as Tay-Sachs disease [9]. 

Intralysosomal substrate storage represents the initial insult to cells by-products of intermediary metabolism (e.g., psychosine in globoid cell leukodytrorphy), a disruption of normal lysosome function, and/or the consequent deficiency in recycling of certain substrates are putative disease events (Ballabio and Gieselmann,... 

Chauhan SS, Liang XJ, Su AW, Pai-Panandiker A, Shen DW, Hanover JA, Gottesman MM. Reduced endocytosis and altered lysosome function in cisplatin-resistant cell lines. Brit. J. Cancer 51. 2003 88 1327-1334. 

In addition to an external cell membrane (called the plasma membrane), eukaryotic cells also contain internal membranes that form the boundaries of organelles such as mitochondria, chloroplasts, peroxisomes, and lysosomes. Functional specialization in the course of evolution has been closely linked to the formation of such compartments. Specific systems have evolved to allow targeting of selected proteins into or through particular internal membranes and, hence, into specific organelles. External and internal membranes have essential features in common, and these essential features are the subject of this chapter. 

I-cell disease A-Acetylglucosaminyl- 1-phosphotransferase Incorrect packaging of lysosomal enzymes impairing lysosome function... 

Root, R. K., Rosenthal, A. S., and Balestra, D. J., Abnormal bactericidal, metabolic and lysosomal functions of Chediak-Higashi syndrome leukocytes. ]. Clin. Invest. 51, 649-665 (1972). 

Lysosomes function in intracellular and extracellular digestion. They are capable of degrading most biomolecules. Lysosomes participate in the life of a cell in three fundamental ways (1) digestion of food molecules or other substances taken into the cell by endocytosis (a process illustrated in Figure 2.22), (2) digestion of worn out or unnecessary cell components, and (3) breakdown of extracellular material. 

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