Truncated TrkB-T1 mediates neurotrophin-evoked calcium signalling in glia cells.
Nature
; 426(6962): 74-8, 2003 Nov 06.
Article
em En
| MEDLINE
| ID: mdl-14603320
ABSTRACT
The neurotrophin receptor TrkB is essential for normal function of the mammalian brain. It is expressed in three splice variants. Full-length receptors (TrkB(FL)) possess an intracellular tyrosine kinase domain and are considered as those TrkB receptors that mediate the crucial effects of brain-derived neurotrophic factor (BDNF) or neurotrophin 4/5 (NT-4/5). By contrast, truncated receptors (TrkB-T1 and TrkB-T2) lack tyrosine kinase activity and have not been reported to elicit rapid intracellular signalling. Here we show that astrocytes predominately express TrkB-T1 and respond to brief application of BDNF by releasing calcium from intracellular stores. The calcium transients are insensitive to the tyrosine kinase blocker K-252a and persist in mutant mice lacking TrkB(FL). By contrast, neurons produce rapid BDNF-evoked signals through TrkB(FL) and the Na(v)1.9 channel. Expression of antisense TrkB messenger RNA strongly reduces BDNF-evoked calcium signals in glia. Thus, our results show that, unexpectedly, TrkB-T1 has a direct signalling role in mediating inositol-1,4,5-trisphosphate-dependent calcium release; in addition, they identify a previously unknown mechanism of neurotrophin action in the brain.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neuroglia
/
Processamento Alternativo
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Fator Neurotrófico Derivado do Encéfalo
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Sinalização do Cálcio
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Receptor trkB
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article