Succinyl concanavalin A stimulates and antimicrotubular drugs inhibit the synthesis of a brain-specific protein in rat glial cells.

The relative synthesis of the brain-specific s100 protein increased as clonal rat glial cells, C6, progressed from logarithmic to stationary growth in monolayer culture. Drugs that disrupt microtubules, such as colchicine, vinblastine, Colcemid, and podophyllotoxin, inhibited the relative synthesis of S100 protein in stationary cultures. Colchicine (0.1 muM) caused a 50% inhibition of the relative synthesis of S100 protein whereas lumicolchicine,an isomer of colchicine that does not disrupt the microtubular system, had no effect. Succinylated concanavalin A (500 mug/ml) increased relative synthesis in logarithmic but not stationary cultures. These results suggest that signals inducing an increase in the relative synthesis of S100 protein in stationary cultures are transmitted intracellularly from the cell membrane by the microtubular network.