Proteins involved in nicotine receptor clustering

One type of nicotinic receptor that has generated a lot of recent interest is one that contains the a7 nicotinic receptor. These receptors are one of the most abundant nicotinic receptors in the nervous system, they are activated by low concentrations of nicotine, and are efficient in letting calcium enter the neuron. The fact that these receptors let calcium enter the neuron means that these receptors can influence a number of calcium-dependent processes within the neuron. Thus, these receptors have been implicated in numerous physiological processes in the developing and adult nervous systems. Many of the neurons which express nicotinic receptors position the receptors in discrete locations or clusters on the cell surface. This compartmentalization of the receptors on the neuron allows for precise activation of subsets of receptors, distinct signaling to the interior of the cell, and separate regulatory control of receptor populations. How the receptors are positioned at distinct sites on the neuron is not known.

It is the goal of this project to determine the proteins involved and the mechanisms used in localizing or clustering nicotinic receptors on neurons. The proposed experiments will visualize receptor clusters on neurons using fluorescent probes and light microscopy. The involvement of other proteins in the clustering of the receptors will be tested by disrupting these proteins and monitoring the receptor clusters. In addition, novel clustering proteins will be identified as associated proteins that purify in combination with the receptor. Lastly, the proteins and mechanisms identified in one neuronal system will then be tested in another neuronal system to validate the universality of these phenomena. These results will provide basic information regarding the function and regulation of the receptors which mediate nicotine’s effects. Understanding the receptors involved and the physiological processes affected by nicotine will be useful in designing new treatments for nicotine addiction and in determining the role these receptors play in human behaviors that initiate tobacco use.