Structural and functional protein network analyses predict novel signaling functions for rhodopsin

Proteomic analyses, literature mining, and structural data were combined to generate an extensive signaling network linked to the visual G protein-coupled receptor rhodopsin. Network analysis suggests novel signaling routes to cytoskeleton dynamics and vesicular trafficking

Glycoprotein requirement for neurite outgrowth in goldfish retina explants: Effects of tunicamycin

The role of glycoproteins in neurite outgrowth in vitro has been examined using the protein glycosylation inhibitor, tunicamycin. The concentration-dependent inhibitory effects of tunicamycin on neuritic outgrowth from goldfish retinal explants closely paralleled its effects on the dolichol pathway of glycoprotein biosynthesis. The neurite membrane assembled in the presence of an intermediate dose of tunicamycin (5 [mu]g/ml) was deficient in carbohydrate, as indicated by a reduced capacity to bind the lectins Concanavalin A, wheat germ agglutinin and ricin. These results suggest that tunicamycin may prove useful in assessing the role of cell surface carbohydrate in neuronal recognition phenomena.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23952/1/0000199.pd

Continued search for the cellular signals that regulate regeneration of dopaminergic neurons in goldfish retina

Intraocular injections of low doses (0.7-1.4 mM estimated intraocular concentration) of 6-hydroxydopamine (6OHDA) selectively destroy dopaminergic neurons in the inner nuclear layer (INL) of goldfish retina, and they never regenerate. However, injection of a higher dose of 6OHDA (2.9 mM) destroys > 30% (but not all) of the cells in both the INL and the outer nuclear layer (ONL), but within 3 weeks, neurons in both the INL (including dopaminergic neurons) and the ONL regenerate. We hypothesize that the regenerated neurons derive from mitotic rod precursors in the ONL and that damage to the surrounding micro-environment (i.e. destruction of photoreceptors) triggers the regenerative response. To directly test this hypothesis, we selectively ablated > 99% of dopaminergic neurons (with low doses of 60HDA) and up to 55% of rod photoreceptors (with tunicamycin), and asked whether the dopaminergic neurons regenerated, as evidenced by double immunolabeling with anti-tyrosine hydroxylase and anti-bromodeoxyuridine. After 38 days, the number of bromodeoxyuridine-immunoreactive rod nuclei was increased 2.4-fold compared to controls, but no regenerated dopaminergic neurons were found. These data suggest that although the rate of rod production increases, rod precursors do not alter their normal pathway of development to replace dopaminergic neurons in the INL when damage to the ONL is limited to destruction of rods.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30390/1/0000008.pd