Disease relevance of ACB1

• Muller cells may secrete ACBP in the inner plexiform layer, thereby decreasing the sensitivity of GABA(A) receptors expressed on the surface of ganglion cell dendrites [1].

High impact information on ACB1

• Much work on the biochemical properties regarding the ACBP has been performed using various vertebrate and plant tissues, as well as different types of cells in culture, the regulatory mechanisms underlying ACBP gene expression have remained poorly understood [2].
• A conditional knockout strain (Y700pGAL1-ACB1) with the ACB1 gene under control of the GAL1 promoter exhibited an altered acyl-CoA profile with a threefold increase in the relative content of C18:0-CoA, without affecting total acyl-CoA level as previously reported for an adapted acb1Delta strain [3].
• The plasma membrane of the Acb1p-depleted strain contained increased levels of inositol-phosphoceramide and mannose-inositol-phosphoceramide and lysophospholipids [3].
• Unsaturated fatty acid repression of OLE1 transcription, however, is not affected by the disrupted ACBP gene [4].
• 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 [5].

Biological context of ACB1

• Two polyadenylation sites, spaced 225 bp apart, are present in the S. cerevisiae ACB1 gene [6].
• The type 1 gene is identical to the S. cerevisiae ACB1 gene except for three substitutions, one single base pair deletion and one double base pair insertion, all located in the promoter region [6].
• The amino acid sequence of S. carlsbergensis ACBP type 1 was found to be identical with the one ACBP present in Saccharomyces cerevisiae [7].
• Nearly all of the ACBP-containing bacteria are pathogenic to plants or animals, suggesting that an ACBP gene could have been acquired from a eukaryotic host by horizontal gene transfer [8].
• In the present study, we show that depletion of acyl-CoA-binding protein, Acb1p, in yeast affects ceramide levels, protein trafficking, vacuole fusion and structure [9].

Anatomical context of ACB1

• Mass spectrometric analysis revealed a dramatic reduction in the content of ceramides in whole-cell lipids and in vacuoles isolated from Acb1p-depleted cells [9].
• ACBP does not cross the blood-brain barrier [1].
• ACBP was localized to Muller glial cells by hybridization histochemistry and by immunohistochemistry [1].
• The X-ray structure of the tetragonal form of apo acyl-CoA-binding protein (ACBP) from the Harderian gland of the South American armadillo Chaetophractus villosus has been solved [10].

Associations of ACB1 with chemical compounds

• The heterologously expressed bovine ACBP constituted up to 6.4% of total cellular protein and the processing was identical with that of native bovine ACBP, i.e. the initiating methionine was removed and the following serine residue was N-acetylated [11].
• We suggest that the reduced ceramide synthesis in Acb1p-depleted cells leads to severely altered vacuole morphology, perturbed vacuole assembly and strong inhibition of homotypic vacuole fusion [9].
• The interaction was also confirmed by a "pull-down" assay in which histidine-tagged ACBP was used to pull down the GABA(A)alpha1 [1].
• Acyl-CoA-binding protein (ACBP) mRNA was one of four mRNAs selected by this screen, the proteins of which interact with GABA receptors [1].

Other interactions of ACB1

• The fact that Gas1p maturation is unaffected by Acb1p depletion, despite the lowered ceramide content in these cells, indicates that ceramide synthesis in yeast could be compartmentalized [9].

Analytical, diagnostic and therapeutic context of ACB1

• Finally, Southern-blotting analysis of the two genes encoding ACBP types 1 and 2 in S. carlsbergensis strongly indicated that this species is a hybrid between S. cerevisiae and Saccharomyces monacensis [7].

References