Role of microtubuli in the lysosomal degradation of endogenous and exogenous protein in isolated rat hepatocytes.

Colchicine and vinblastine, two well known inhibitors of microtubular function, inhibited endogenous protein degradation as well as protein secretion and the degradation of an exogenous, internalized protein (asialo fetuin), in isolated rat hepatocytes. The inhibitors appeared to selectively affect the lysosomal pathway of degradation, since their effects were not additive to that of ammonia, a lysosomotropic degradation inhibitor.