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Dephosphorylation-induced decrease of anti-apoptotic function of Bcl-2 in neuronally differentiated P19 cells
H Yokote1, T Terada, H Matsumoto
1Department of neurosurgery, Wakayama Medical College, Kimiidera 811-1, Wakayama, Japan. hyokote@wakayama-med.ac.jp
Brain Research
|March 4, 2000
Summary
The phosphorylation state of Bcl-2, not just its level, impacts its protective role against neuronal ischemia. Dephosphorylated Bcl-2 is linked to increased apoptosis following energy impairment.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Bcl-2 protein is known to protect neurons from ischemic injury.
- The anti-apoptotic function of Bcl-2 may depend on its phosphorylation state rather than expression levels.
Purpose of the Study:
- To investigate the role of Bcl-2 phosphorylation in neuronal apoptosis induced by energy impairment.
- To compare the protective effects of wild-type Bcl-2 and a phosphorylation-deficient mutant against ischemic insults.
Main Methods:
- Induced apoptosis in differentiated P19 cells using energy impairment (3-nitropropionic acid or glucose deprivation).
- Analyzed Bcl-2 phosphorylation status and cell viability over time.
- Generated cell lines overexpressing wild-type Bcl-2 or a phosphorylation-negative mutant (Ser70 to Alanine).
Main Results:
- Energy impairment led to increased apoptosis and CPP32 activation, correlating with decreased dephosphorylated Bcl-2.
- Cells overexpressing the phosphorylation-negative Bcl-2 mutant were more vulnerable to energy impairment.
- Wild-type Bcl-2 overexpression inhibited DNA laddering and CPP32 activation, while the mutant did not.
Conclusions:
- Bcl-2 phosphorylation state is crucial for its protective effect against ischemic insults.
- Both expression level and phosphorylation status of Bcl-2 modulate its anti-apoptotic function in neurons.