Accession Number:
ADA267121
Title:
Modulation of Ionic Channel Function by Protein Phosphorylation
Descriptive Note:
Final rept. 15 Mar 89-14 Oct 92,
Corporate Author:
CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF BIOLOGY
Personal Author(s):
Report Date:
1992-11-12
Pagination or Media Count:
55.0
Abstract:
Protein phosphorylation is considered a key event in synaptic physiology. The acetylcholine receptor AChR, a prototype of ligand-gated ion channels, plays a central role in postsynaptic signal transduction. To examine the functional consequences of AChR phosphorylation, single-channel properties of purified Torpedo californica AChR reconstituted in planar lipid bilayers, were evaluated before and after phosphorylation by purified protein-serine and - tyrosine kinases, or dephosphorylation by recombinant protein tyrosine phosphatase. Single-channel conductance was not altered by changing the AChR serine or tyrosine phosphorylation state. In contrast, the AChR open-channel probability was markedly affected both by the extent of receptor phosphorylation in different subunits and by agonist concentration. Notably, the spontaneous open-channel probability of serine-phosphorylated AChRs is significantly higher than that of AChRs phosphorylated on tyrosine residues or of unphosphorylated AChRs. Channel activation by protein kinase A and protein kinase C is correlated with AChR phosphorylation and is abolished by alpha-bungarotoxin.... Protein phosphorylationion channels, RA1
Descriptors:
- *IONS
- *PROTEINS
- *CHANNELS
- *PHOSPHORYLATION
- FREQUENCY
- CONTRAST
- ACTIVATION
- PROBABILITY
- PROTOTYPES
- DEOXYRIBONUCLEIC ACIDS
- GAMMA RAYS
- PHOSPHATASES
- CHEMORECEPTORS
- ACETYLCHOLINE
- SERINE
- TYROSINE
- RESIDUES
- CURRENTS
- SYNAPSE
- PHYSIOLOGY
- NICOTINE
- PHOSPHORUS TRANSFERASES
- LIGANDS
- SENSITIVITY
- SODIUM
- COVALENT BONDS
- CONDUCTIVITY
- MODIFICATION
- LIPIDS
Subject Categories:
- Anatomy and Physiology
- Medicine and Medical Research