Lysosomal degradation of membrane lipids.
The constitutive degradation of membrane components takes place in the acidic compartments of a cell, the endosomes and lysosomes. Sites of lipid degradation are intralysosomal membranes that are formed in endosomes, where the lipid composition is adjusted for degradation. Cholesterol is sorted out of the inner membranes, their content in bis(monoacylglycero)phosphate increases, and, most likely, sphingomyelin is degraded to ceramide. Together with endosomal and lysosomal lipid-binding proteins, the Niemann-Pick disease, type C2-protein, the GM2-activator, and the saposins sap-A, -B, -C, and -D, a suitable membrane lipid composition is required for degradation of complex lipids by hydrolytic enzymes.
Kolter
Thomas
T
LiMES - Life and Medical Sciences Institute, Membrane Biology and Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie, University of Bonn, Bonn, Germany.
Sandhoff
Konrad
K
D000818:Animals; D017951:Antigen Presentation / Q000502:physiology; D001692:Biological Transport / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology; D049289:G(M2) Activator Protein / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism / Q000502:physiology*; D008247:Lysosomes / Q000378:metabolism*; D008563:Membrane Lipids / Q000276:immunology / Q000378:metabolism*; D008954:Models, Biological; D049231:Saposins / Q000378:metabolism; D015398:Signal Transduction; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D049289:G(M2) Activator Protein; D006023:Glycoproteins; D008563:Membrane Lipids; C104585:NPC2 protein, human; D049231:Saposins; D033921:Vesicular Transport Proteins