The yeast multidrug transporter Pdr5 of the plasma membrane is ubiquitinated prior to endocytosis and degradation in the vacuole

FEBS Lett. 1996 Jan 8;378(2):177-81. doi: 10.1016/0014-5793(95)01450-0.


We have recently demonstrated that the Pdr5 ATP binding cassette multidrug transporter is a short-lived protein, whose biogenesis involves cell surface targeting followed by endocytosis and delivery to the vacuole for proteolytic turnover [Egner, R., Mahé, Y., Pandjaitan, R., and Kuchler, K. (1995) Mol. Cell. Biol. 15, 5879-5887]. Using c-myc epitope-tagged ubiquitin, we now have shown that Pdr5 is a ubiquitinated plasma membrane protein in vivo. Ubiquitination of Pdr5 was detected in both wild type and conditional end mutants defective in endocytic vesicle formation. Likewise, the Ste6 a-factor pheromone transporter, which represents another short-lived ABC transporter whose turnover requires vacuolar proteolysis, was also found to be ubiquitinated, and ubiquitin-modified Ste6 massively accumulated in end4 mutants at the restrictive temperature. By contrast, the plasma membrane ATPase Pma1, a long-lived and metabolically very stable protein, was found not to be ubiquitinated. Our results imply a novel function for ubiquitin in protein trafficking and suggest that ubiquitination of certain short-lived plasma membrane proteins may trigger their endocytic delivery to the vacuole for proteolytic turnover.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / metabolism*
  • Cell Membrane / chemistry
  • Endocytosis*
  • Fungal Proteins / metabolism*
  • Hemagglutinins
  • Membrane Proteins / metabolism*
  • Saccharomyces cerevisiae / chemistry*
  • Saccharomyces cerevisiae Proteins*
  • Ubiquitins / metabolism*
  • Vacuoles / metabolism*


  • ATP-Binding Cassette Transporters
  • Fungal Proteins
  • Hemagglutinins
  • Membrane Proteins
  • PDR5 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Ubiquitins