Connecting Hsp70, sphingolipid metabolism and lysosomal stability.
Heat shock protein 70 (Hsp70) is an evolutionary highly conserved molecular chaperone. Upon cancer-associated translocation to the lysosomal compartment, it promotes cell survival by inhibiting lysosomal membrane permeabilization, a hallmark of stress-induced death. We have recently shown that Hsp70 stabilizes lysosomes by binding to the endo-lysosomal lipid bis(monoacylglycero)phosphate (BMP), an essential co-factor for lysosomal sphingolipid catabolism. The Hsp70-BMP interaction enhances the activity of acid sphingomyelinase, an important enzyme that hydrolyzes sphingomyelin. Importantly, treatment with recombinant Hsp70 effectively reverts the dramatic increase in lysosomal volume and decrease in lysosomal stability in cells from patients with Niemann-Pick disease, a genetic disorder associated with reduced acid sphingomyelinase activity. These findings give new insight into the mechanisms controlling lysosomal stability and integrity, and open new exciting possibilities for the treatment of cancer as well as Niemann-Pick disease.
Apoptosis Department and Center for Genotoxic Stress Research, Institute of Cancer Biology, Danish Cancer Society, Copenhagen, Denmark.
Nikolaj H T
NH
Petersen
Thomas
T
Kirkegaard
Ole Dines
OD
Olsen
Marja
M
Jäättelä
D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008247:Lysosomes / Q000201:enzymology*; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism; D009542:Niemann-Pick Diseases / Q000235:genetics / Q000378:metabolism; D013107:Sphingolipids / Q000378:metabolism*
D018840:HSP70 Heat-Shock Proteins; D013107:Sphingolipids