Lateral diffusion of the Torpedo and muscle type acetylcholine receptors on oocytes membranes of the Xenopus laevis

CHED 908

Ileana Rodriguez Nazario, ilysax72004@hotmail.com1, Alejandro Ortiz Acevedo, ortizacevedo@yahoo.com2, and Jose A. Lasalde Dominicci, joseal@coqui.net2. (1) Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, P.O. Box 2336, San Juan, PR 00931, (2) Department of Biology, University of Puerto Rico, P.O. Box 2336, San Juan, PR 00931
It is known that extrajunctional diffusion of Acetylcholine receptor (AChR) is essential during synapse formation; however it is not known how this process compares in different AChR subtypes. We use Fluorescence Recovery After Photobleaching (FRAP) in order to study the dynamics of fluorescently-tagged macromolecules on cells. We are applying this technique to obtain quantitative data on the translational diffusion of two types of receptors on oocytes membranes: 1) Torpedo californica WT receptor, and 2). a Torpedo receptor with mutations at various lipid-exposed residues, áS287A, áC412G, âY441W, ãM299V, ãS460I, äM293L, äS297V and äN305I (LEM receptor). The mutations in the LEM receptor result in a Torpedo AChR with electrophysiological characteristics almost identical to that of mouse WT AChR. The experimental fluorescence recovery curves were fit to a one phase exponential decay equation using Graph Pad Prism®. The quantitative data calculated for these different receptors include: the diffusion time constant (K), the percent fluorescence recovery and the time estimated to reach half maximal recovery (half life) of the receptors.

 

Undergraduate Research Poster Session: Biochemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster

Division of Chemical Education

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007