Lipid and cholesterol trafficking in NPC.
Niemann-Pick type C, or NPC for short, is an early childhood disease exhibiting progressive neurological degeneration, associated with hepatosplenomegaly in some cases. The disease, at the cellular level, is a result of improper trafficking of lipids such as cholesterol and glycosphingolipids (GSLs) to lysosome-like storage organelles (LSOs), which become engorged with these lipids. It is believed that the initial defect in trafficking, whether of cholesterol or a GSL, results in an eventual traffic jam in these LSOs. This leads to the retention of not only other lipids, but also of transmembrane proteins that transiently associate with the late endosomes (LE) in normal cells, on their way to other cellular destinations such as the trans-Golgi network (TGN). In this review, we discuss the biophysical properties of lipids and cholesterol that might determine their intracellular itineraries, and how these itineraries are altered in NPC cells, which have defects in the proteins NPC1 or NPC2. We also discuss some potential therapeutic directions being suggested by recent research.
Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.
Sushmita
S
Mukherjee
Frederick R
FR
Maxfield
D000818:Animals; D001692:Biological Transport; D055592:Biophysical Phenomena; D001703:Biophysics; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D004705:Endocytosis; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D050356:Lipid Metabolism; D008247:Lysosomes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D000077296:Niemann-Pick C1 Protein; D009542:Niemann-Pick Diseases / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; C106881:NPC1 protein, human; C104585:NPC2 protein, human; D000077296:Niemann-Pick C1 Protein; D033921:Vesicular Transport Proteins; D002784:Cholesterol