Peter Anderson Subject: Re: IBN-9723438 ABSTRACT Voltage gated calcium channels are a family of proteins that are essential for many cell functions, including excitation, contraction, secretion, enzyme activity and gene regulation. They exist in living cells as multisubunit complexes, usually consisting of an alpha1 subunit and associated beta, gamma and alpha2/delta subunits. The pore forming alpha1 subunits, which are primarily responsible for many of the physiological and pharmacological properties of the channels, can be divided on their basis of their structure, into 6 separate classes. A full length calcium channel cDNA was recently cloned from the jellyfish Cyanea capillata, by our lab. The deduced amino acid sequence of this protein suggests that it is a member of the L-type family of calcium channels, and this is supported by much of its physiology and pharmacology. However, there are some significant deviations from the overall properties of calcium channels, in particular the ionic selectivity of the channel and its sensitivity to dihydropyridines, a class of calcium channel blockers that are diagnostics of L-type calcium channels. The aim of the proposed work is to complete the characterization of the jellyfish calcium channel with a view to using the physiological and pharmacological abnormalities of this channel as a means of identifying the structural correlates of L-type channel function.
