A gene encoding a sphingolipid biosynthesis enzyme determines the sensitivity of Saccharomyces cerevisiae to an antifungal plant defensin from dahlia (Dahlia merckii)
AUTOR(ES)
Thevissen, Karin
FONTE
The National Academy of Sciences
RESUMO
We have previously identified a Saccharomyces cerevisiae mutant that is markedly more resistant than wild-type to Dahlia merckii antimicrobial peptide 1 (DmAMP1), an antifungal plant defensin isolated from seeds of dahlia (Dahlia merckii). A complementation approach was followed that consisted of the introduction of a genomic library of DmAMP1-sensitive wild-type yeast into the DmAMP1-resistant yeast mutant and screening for restored sensitivity to DmAMP1. The gene determining sensitivity of S. cerevisiae to DmAMP1 was identified as IPT1, a gene encoding an enzyme involved in the last step of the synthesis of the sphingolipid mannose-(inositol-phosphate)2-ceramide. Strains with a nonfunctional IPT1 allele lacked mannose-(inositol-phosphate)2-ceramide in their plasma membranes, bound significantly less DmAMP1 compared with wild-type strains, and were highly resistant to DmAMP1-mediated membrane permeabilization. All of these phenotypic deviations could be restored by reintroduction of a functional IPT1 gene. Our data support a model in which membrane patches containing sphingolipids act as binding sites for DmAMP1 or, alternatively, are required to anchor membrane or cell wall-associated proteins, which themselves interact with DmAMP1.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=16899Documentos Relacionados
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