E. Riballo et al., CATABOLITE INACTIVATION OF THE YEAST MALTOSE TRANSPORTER OCCURS IN THE VACUOLE AFTER INTERNALIZATION BY ENDOCYTOSIS, Journal of bacteriology, 177(19), 1995, pp. 5622-5627
The maltose transporter of Saccharomyces cerevisiae is rapidly degrade
d during fermentation in the absence of a nitrogen source. The locatio
n and mechanism of degradation of the transporter have been investigat
ed. Using mutants defective in endocytosis, we have shown that degrada
tion of this transporter requires internalization by endocytosis. In a
ddition, studies of mutants defective in proteasome or vacuolar proteo
lysis revealed that degradation occurs iii the vacuole and is independ
ent of proteasome function. The results also revealed that degradation
of the maltose transporter requires Sec18p and raised the question of
whether in the absence of Sec18p activity the internalized maltose tr
ansporter is recycled back to the plasma membrane.