Microtubule assembly in cultivated Greene melanoma cells is stimulated by dibutyryl adenosine 3':5'-cyclic monophosphate or cholera toxin.

Abstract

Dibutyryl cyclic AMP (DBcAMP) and cholera toxin promote the formation and elongation of processes of cultivated Greene hamster melanoma cells. The formation and maintenance of these processes, which contain many microtubules, are sensitive to Colcemid and vinblastine. Tubulin was measured by [3H]colchicine binding and acrylamide gel electrophoresis. DBcAMP or cholera toxin increases the ratio of polymerized to unpolymerized tubulin but not the total amount of tubulin per cell. The sum of the lengths of microtubules per unit area was greater in cells treated with DBcAMP than in control cells. cAMP may promote the elongation of cell processes by stimulating the assembly of microtubules from existing tubulin.