Co-lethality of LEU2 and BAP2 is carbon source dependent and is overcome by BUL1 deletion in Saccharomyces cerevisiae

Abstract

In a leucine requiring Saccharomyces cerevisiae strain, deletion of BAP2, a high affinity leucine permease confers lethality in presence of fermentable sugars, but not other carbon sources. Deletion of BUL1, an adaptor overcomes this lethality. BUL1 deletion augments leucine import through accumulation of Bap3 and Bap2 in the plasma membrane and reduces their turnover. We suspect BUL1 as a cognate adaptor for ubiquitylation of these permeases.