An inducible, specific and derepressible transport of L-serine in Saccharomyces cerevisiae

Abstract

Both rho⁺ and rho⁻ cells were capable of accumulating L-serine against a concentration gradient; however, the extent of serine accumulation differed between these two strains. About 60% of the total accumulation of serine was reduced in rho⁻ cells which were shown to lack functional mitochondria. The transport of serine was mediated via a specific and an inducible system. It was also derepressible under nitrogen-starved conditions. The derepression of L-serine uptake was also evident under conditions where general amino-acid permease is not expressed.