Hai-Qing Chen

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Nucleoside diphosphate kinase (NDPK) catalyzes the transfer of terminal phosphates from nucleoside triphosphates to nucleoside diphosphates to yield nucleotide triphosphates. The present study was undertaken to localize and characterize the mitochondrial isoform of NDPK (mNDPK) in the pancreatic beta cell since it could contribute to the generation of(More)
We recently demonstrated that functional inactivation of H-Ras results in significant reduction in interleukin 1 beta (IL-1 beta)-mediated effects on isolated beta cells. Since palmitoylation of Ras has been implicated in its membrane targeting, we examined the contributory roles of palmitoylation of Ras in IL-1 beta-induced nitric oxide (NO) release and(More)
Mastoparan, a tetradecapeptide from wasp venom, stimulates insulin secretion from the islet beta-cells, presumably via activation of trimeric G proteins. Herein, we used Clostridial toxins, which selectively modify and inactivate the Rho subfamily of G proteins, to examine whether mastoparan-induced insulin secretion also involves activation of these(More)
The majority of low molecular weight G proteins undergoes a series of post-translational modification steps, e.g., isoprenylation, at their C-terminal cysteine, which seem to be critical for the transport of the modified proteins to the membrane sites for interaction with their respective effector proteins. Using lovastatin, an inhibitor of mevalonic acid,(More)
We have previously demonstrated regulatory roles for Rho subfamily of G-proteins in glucose- and calcium-induced insulin secretion. Herein, we examined regulation by these proteins of insulin secretion from betaTC3 cells elicited by mitochondrial fuels, such as the succinic acid methyl ester (SAME). Preincubation of these cells with Clostridium difficile(More)
Myo-(H]inositol accumulation in cultured bovine lens epithelial cells (BLECs) occurred by highand low-affinity, Na-dependent transport sites. The highand low-affinity transport systems had a Km of 27 ± 4 and 157 ± 22 fimol/l, respectively, and Vmax of 652 ± 35 and 2952 ± 308 pmol/mg protein/hr, respectively. The uptake of myo-[H]inositol was lowered after(More)
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