A genomic screen identifies AUT8 as a novel gene essential for autophagy in the yeast Saccharomyces cerevisiae

Autophagy is a starvation-induced transport pathway delivering parts of the cytosol into the lysosome (vacuole) for degradation. Autophagy significant ly differs from other transport pathways by using double membrane layered t ransport intermediates. Based on the identification of autophagy genes in S accharomyces cerevisiae, which served as a pacemaker for higher cells, our mechanistic knowledge of autophagy notably increased over the past few year s. We here identify A UT8 as a novel gene essential for autophagy by screen ing a collection of similar to 5000 yeast deletion strains, each containing a defined deletion in an individual gene. This collection is a result of t he world-wide Saccharomyces deletion project and covers the non-essential g enes of the whole yeast genome. Homozygous aut8 Delta cells are impaired in maturation of proaminopeptidase I, and they fail to undergo the cell diffe rentiation process of sporulation. The essential function of A UT8 for auto phagy is further demonstrated by the lack of accumulation of autophagic ves icles in the vacuoles of aut8 Delta cells starved of nitrogen in the presen ce of the proteinase B inhibitor phenylmethylsulfonyl fluoride. (C) 2001 El sevier Science B.V. All rights reserved.