A caspase cascade regulating developmental axon degeneration.
J Neurosci
; 32(49): 17540-53, 2012 Dec 05.
Article
em En
| MEDLINE
| ID: mdl-23223278
ABSTRACT
Axon degeneration initiated by trophic factor withdrawal shares many features with programmed cell death, but many prior studies discounted a role for caspases in this process, particularly Caspase-3. Recently, Caspase-6 was implicated based on pharmacological and knockdown evidence, and we report here that genetic deletion of Caspase-6 indeed provides partial protection from degeneration. However, we find at a biochemical level that Caspase-6 is activated effectively only by Caspase-3 but not other "upstream" caspases, prompting us to revisit the role of Caspase-3. In vitro, we show that genetic deletion of Caspase-3 is fully protective against sensory axon degeneration initiated by trophic factor withdrawal, but not injury-induced Wallerian degeneration, and we define a biochemical cascade from prosurvival Bcl2 family regulators to Caspase-9, then Caspase-3, and then Caspase-6. Only low levels of active Caspase-3 appear to be required, helping explain why its critical role has been obscured in prior studies. In vivo, Caspase-3 and Caspase-6-knockout mice show a delay in developmental pruning of retinocollicular axons, thereby implicating both Caspase-3 and Caspase-6 in axon degeneration that occurs as a part of normal development.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Axônios
/
Colículos Superiores
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Caspase 3
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Caspase 6
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Degeneração Neural
Limite:
Animals
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article