The long term objective of this research is to define, at the molecular level, the mechanism of neurotransmitter release, neural cell secretion, which is the basis for the reception of sensations, thought integration and response initiation. The approach to be taken is to study the nerve ending calcium-binding proteins since increased concentrations in the nerve ending appear to be the only absolute requirement for release. Unlike other, slower forms of secretion, the quickness of neurotransmitter release suggests that calcium-binding proteins probably are involved directly. The project will investigate calcium binding to alpha-actinin which binds F-actin and bundles actin filaments. Also alpha-actinin which believed to occur at nerve endings. Specifically, techniques will be applied to measure 45Ca2+ binding to alpha-actinin, localize the calcium binding sites, study the competition by other cations for these sites, investigate conformational and functional changes produced by cations using flow dialysis, gel electrophoresis, protein blotting and 45Ca overlay, column chromatography, fluorescence and circular dichroism measurements. These studies will reveal the interactions of alpha-actinin with calcium and illuminate its possible roles in neurotransmitter release.
