Disruption of the Gene Encoding the Acyl-CoA-binding Protein ( ) Perturbs Acyl-CoA Metabolism in

Abstract

The ACB1 gene encoding the acyl-CoA-binding protein (ACBP) was disrupted in Saccharomyces cerevisiae. The disruption did not affect the growth rate on glucose but reduced the growth rate on ethanol slightly. Although the growth rate of the acb1-disrupted cells was unaffected or only slightly affected, the acb1-disrupted strain was unable to compete with wild type cells when grown in mixed culture. The acyl-CoA level in the disrupted cells was increased from 1.5- to 2.5-fold during exponential growth. The increase in the acyl-CoA level was caused solely by an increase in de novo synthesized stearoyl-CoA. Experiments with purified yeast fatty acid synthetase show that it will synthesize long chain acyl-CoAs in the absence of acyl-CoA-binding protein. The addition of ACBP to the incubation medium resulted in a dramatic decrease in the chain length of the synthesized acyl-CoA esters. Despite the fact that the stearoyl-CoA concentration was increased 7-fold and the Delta9-desaturase mRNA level was increased 3-fold, the synthesis of oleic acid was unchanged in the acb1-disrupted strain. The results strongly indicate that ACBP in yeast is involved in the transport of newly synthesized acyl-CoA esters from the fatty acid synthetase to acyl-CoA-consuming processes.

Acyl Carriers Used as Substrates by the Desaturases and Elongases Involved in Very Long-chain Polyunsaturated Fatty Acids Biosynthesis Reconstituted in Yeast

“…acyl-CoA thioesters versus lipid-bound oxygen esters, this result is not surprising. Quantitative acyl-CoA measurements with yeast have shown that lipid-bound acyl groups exceed acyl-CoA thioesters by a factor of about 2000 (35). With the method used in the present study and in the presence of 500 M exogenous fatty acid, we found even larger factors (data not shown).…”

Biochemistry, cell biology and molecular biology of lipids ofSaccharomyces cerevisiae

“…41,176 An acyl-CoA binding protein, Acb1p, is thought to bind the acyl chain and hand it over to cellular processes that consume acyl-CoA. 220 173,253 The encoding gene, OLE1/MDM2, has been demonstrated to be also involved in partitioning of mitochondria between mother and daughter cells. The ole1/mdm2 mutants are viable when fed unsaturated fatty acids.…”

Catabolism of hydroxyacids and biotechnological production of lactones by Yarrowia lipolytica

“…These proteins, initially discovered as an impurity in a FABP preparation (Mogensen et al 1987), constitute a family that is well conserved over all eukaryotic species (Knudsen et al 1999). In yeast, overexpression experiments have shown its role in acylCoA pool formation (Mandrup et al 1993;Knudsen et al 1994); and gene disruption strongly suggests a role in transport (Schjerling et al 1996).…”