FIG. 1.

Internalization and degradation of the maltose transporter in a mutant defective in clathrin. Strains GPY1100 (CHC1, wild type [WT]; ○) and GPY 418 (chc1-1; ▵), transformed with the plasmid pRM1-1 carrying the MAL1 locus, were harvested during exponential growth at 24°C, washed, and suspended in 3 volumes of the endocytosis medium. After incubation at 24°C (A and C) or 35°C (B and D) for the indicated times, the cells were harvested and assayed for maltose transporter activity (A and B). The maltose transporter band was detected by immunoblotting aliquots, containing 40 μg of protein of cellular extracts obtained at the indicated times (C and D).