EFFECT OF ANTIMICROTUBULAR DRUGS ON THE SECRETION PROCESS OF EXTRACELLULAR PROTEINS IN ASPERGILLUS-NIDULANS

The role of microtubules (MTs) in the protein secretion process in Aspergillus nidulans has been studied using two antimicrotubular drugs, methyl benzimadazol-2-yl carbamate (MBC) and griseofulvin, and two strains of A. nidulans: a wild-type and a benomyl resistant-mutant (ben A10). Sublethal doses of MBC and griseofulvin reduced the total amount of proteins secreted by the wildtype strain and modified the electrophoretic pattern of the extracellular proteins, inhibiting the secretion of certain proteins and favouring the secretion of several others that were not secreted in the control cultures. Some of these modifications were the same with both antimicrotubular compounds. MBC did not alter either the amount of proteins secreted or the electrophoretic patterns of proteins in the A. nidulans benomyl-resistant strain, demonstrating that its action is mediated via the microtubules. Our results suggest the involvement of MTs in the polarized secretion process of A. nidulans.