Lipophilic vanadium compounds drive translocation of insulin receptors into rafts

INOR 78

Deborah A Roess, daroess@lamar.colostate.edu1, Steven M L Smith, stevenm@lamar.colostate.edu1, Alvin A. Holder, aaholder@yahoo.com2, and Debbie C. Crans, crans@lamar.colostate.edu2. (1) Department of Biomedical Sciences, Colorado State University, Campus Mail 1872, Fort Collins, CO 80523, (2) Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872
Signal transduction via plasma membrane proteins in cells may occur following translocation of proteins including the insulin receptor (IR) into specialized membrane compartments such as “rafts”. We examined the effects of a lipophilic vanadium compound on IRs and other membrane proteins that use rafts as signaling platforms. Cells were treated with non-toxic concentrations of [VOsal-Tris]2, formed from a condensation reaction between salicylaldehyde and tris(hydroxymethyl)aminomethane. [VOsal-Tris]2 treatment resulted in translocation of IR from the bulk membrane into rafts in the absence of insulin. Moreover, both insulin and [VOsal-Tris]2, over a broad range of concentrations, caused cell degranulation, a response linked to activation of plasma membrane receptors that partition into rafts. Thus, V compounds, in addition to crossing the plasma membrane, may function as anti-diabetes agents by intercalating in lipid interfaces. Intercalation of V compounds in lipids has been suggested by recent evidence using 51V and 1H NMR spectroscopy to determine the placement of [VO2dipic]- in reverse micelles.
 

Bioinorganic Chemistry of Vanadium Compounds
2:00 PM-5:40 PM, Sunday, 10 September 2006 Moscone Center -- Room 304, Oral

Division of Inorganic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006