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Channel modulation by tyrosine phosphorylation in an identified leech neuron
L Aniksztejn1, S Catarsi, P Drapeau
1Centre for Research in Neuroscience, McGill University, Montreal, Quebec, Canada.
The Journal of Physiology
|January 1, 1997
Summary
Tyrosine dephosphorylation increases cation channel activity in leech neurons. This suggests that dephosphorylation constitutively modulates channel function under resting conditions, impacting neuronal signaling.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Pressure-sensitive (P) neurons in leeches play a role in sensory modulation.
- Cation channels are crucial for neuronal excitability and signaling.
- Tyrosine phosphorylation is a key post-translational modification regulating protein function.
Purpose of the Study:
- To investigate the impact of tyrosine phosphorylation on the activity of a spontaneously active cation channel in leech P neurons.
- To determine if modulating tyrosine phosphorylation levels affects cation channel function.
Main Methods:
- Utilized cell-attached and inside-out patch-clamp recordings from cultured leech P neurons.
- Administered genistein (tyrosine kinase inhibitor) and pervanadate (tyrosine phosphatase inhibitor).
- Applied a catalytically active tyrosine phosphatase fragment and orthovanadate.
Main Results:
- Genistein significantly increased cation channel activity in intact P cells, while daidzein had no effect.
- Pervanadate blocked the effect of genistein, indicating a role for tyrosine kinases.
- In isolated patches, a tyrosine phosphatase fragment increased channel activity, which was inhibited by orthovanadate.
Conclusions:
- Basal cation channel activity is enhanced by tyrosine dephosphorylation.
- This suggests a mechanism for constitutive modulation of channel activity under resting conditions.
- Tyrosine phosphorylation state dynamically regulates cation channel function in P neurons.