Regulation of the tubulin polymerization-promoting protein by Ca/S100 proteins.

To elucidate S100 protein-mediated signaling pathways, we attempted to identify novel binding partners for S100A2 by screening protein arrays carrying 19,676 recombinant glutathione S-transferase (GST)-fused human proteins with biotinylated S100A2. Among newly discovered putative S100A2 interactants, including TMLHE, TRH, RPL36, MRPS34, CDR2L, OIP5, and MED29, we identified and characterized the tubulin polymerization-promoting protein (TPPP) as a novel S100A2-binding protein. We confirmed the interaction of TPPP with Ca/S100A2 by multiple independent methods, including the protein array method, S100A2 overlay, and pulldown assay in vitro and in transfected COS-7 cells.

Interaction of S100A6 with Target Proteins In Vitro and in Living Cells.

S100A6 is a member of the EF-hand Ca-binding protein family, which plays important roles in a wide variety of Ca signaling in the cells, as well as in pathophysiological conditions. Herein, we describe analytical protocols for evaluating the interaction of S100A6 with multiple target proteins in vitro, including biotinylated S100A6 overlay, glutathione-S-transferase (GST)-precipitation, surface plasmon resonance, and a GST-precipitation assay in living cells. These methods will elucidate the detailed molecular mechanisms of S100A6/target interactions and further improve our understanding of the physiological significance of S100A6-mediated Ca signaling.

Increased conversion of tryptophan to nicotinamide in rats by dietary valproate.

Valproic acid (VPA) is a short-chained, branched fatty acid that is widely used in humans as an anticonvulsant and mood stabilizer, and has been reported to increase the liver NAD concentration. We investigated the effects of VPA on the conversion of tryptophan to nicotinamide. Rats were fed diets containing various amounts of VPA (0, 0.