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Apoptosis and signalling in acid sphingomyelinase deficient cells
1Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK. dan@glycob.ox.ac.uk
BMC Cell Biology
|November 28, 2001
Summary
Cells deficient in acid sphingomyelinase may have impaired apoptosis signaling due to sphingomyelin accumulation. This leads to raft formation, sequestering signaling molecules and impacting cellular function.
Area of Science:
- Cell Biology
- Biochemistry
- Apoptosis Signaling
Background:
- Apoptosis involves sphingomyelin flipping and ceramide production, promoting plasma membrane blebbing for phagocytosis.
- Contradictory evidence shows acid sphingomyelinase-deficient cells have defective apoptosis signaling.
- This suggests acid sphingomyelinase activation is an early apoptosis signal.
Purpose of the Study:
- To propose an alternative explanation for defective apoptosis in acid sphingomyelinase-deficient cells.
- To investigate the role of intracellular sphingomyelin accumulation and raft formation in sequestering signaling molecules.
Main Methods:
- Examining the subcellular distribution of signaling molecules in acid sphingomyelinase-deficient cells.
- Assessing if signaling molecule sequestration occurs in late endosomes/lysosomes.
- Comparing these findings with other sphingolipid storage diseases like Niemann-Pick type C.
Main Results:
- Acid sphingomyelinase deficiency is hypothesized to cause intracellular sphingomyelin accumulation.
- This accumulation may lead to the formation of intracellular rafts.
- These rafts could sequester essential cell surface signaling molecules.
Conclusions:
- The hypothesis provides a cellular mechanism for sphingolipid storage disease pathology.
- It offers insights into the role of ceramide in apoptosis.
- Altered subcellular distribution of signaling molecules is key to this proposed mechanism.