Analysis of protein expression and compartmentalization in retinal neurons using serial tangential sectioning of the retina.

The progress in understanding visual signal transduction in vertebrate photoreceptors, arguably the best studied G protein-mediated signal transduction cascade in modern biology, was facilitated by the unique anatomy of rod photoreceptors. Held only by thin connected cilia, rod outer segments can be readily separated from the rest of the retina simply by shaking, and then purified by gradient centrifugation. The availability of such an efficient procedure of rod outer segment purification not only previously facilitated the identification of many principal visual signaling proteins located in this cellular compartment, but it is also currently being exploited in proteomics studies. In this paper, we describe a simple and inexpensive technique that allows for the quantitative analysis of protein expression within different subcellular compartments of photoreceptors, and could also be used for studying protein expression in the secondary retinal neurons. This technique is based on the Western blot analysis ...