Fatty acid uptake in the Saccharomyces cerevisiae mutant mon2

Abstract

The yeast MON2 gene product is a scaffolding protein involved in vesicular budding on the trans‐Golgi membrane. We have found that the mon2Δ mutant shows increased growth sensitivity to undecylenic acid (11:1Δ10), a medium chain unsaturated fatty acid (UFA), compared to wild type cells under the same growth conditions. In order to better understand this effect, we examined wild type and mutant mon2Δ responses in unsupplemented, 18:2Δ9,12, and 11:1Δ10 fed conditions. We have found that when Mon2p is absent, there are altered molecular responses to 11:1Δ10 supplementation, including: small but significant changes in the fatty acid profile; differential localization of BODIPY 500/510 C1, C12, a fluorescent fatty acid analog; decreased expression of OLE1, the gene for the delta‐9‐desaturase; and, altered rates of fatty acid uptake. These changes result in decreased synthesis of endogenous UFAs, which may be responsible for the 11:1Δ10 toxicity. These findings suggest a role for Mon2p in the uptake and trafficking of exogenous medium chain fatty acids, possibly through vesicle transport. Supported by awards from the National Science Foundation‐Research Experiences for Undergraduates and a Research Scholar Award from Howard Hughes Medical Institute.