Arabidopsis cytosolic acyl-CoA-binding proteins ACBP4, ACBP5 and ACBP6 have overlapping but distinct roles in seed development

A - Papers appearing in refereed journals

Hsiao, A-S., Haslam, R. P., Michaelson, L. V., Liao, P., Chen, Q-F., Sooriyaarachchi, S., Mowbray, S. L., Napier, J. A., Tanner, J. A. and Chye, M-L. 2014. Arabidopsis cytosolic acyl-CoA-binding proteins ACBP4, ACBP5 and ACBP6 have overlapping but distinct roles in seed development. Bioscience Reports. 34 (6), pp. 865-877.

AuthorsHsiao, A-S., Haslam, R. P., Michaelson, L. V., Liao, P., Chen, Q-F., Sooriyaarachchi, S., Mowbray, S. L., Napier, J. A., Tanner, J. A. and Chye, M-L.
Abstract

Eukaryotic cytosolic ACBPs (acyl-CoA-binding proteins) bind acyl-CoA esters and maintain a cytosolic acyl-CoA pool, but the thermodynamics of their protein–lipid interactions and physiological relevance in plants are not well understood. Arabidopsis has three cytosolic ACBPs which have been identified as AtACBP4, AtACBP5 and AtACBP6, and microarray data indicated that all of them are expressed in seeds; AtACBP4 is expressed in early embryogenesis, whereas AtACBP5 is expressed later. ITC (isothermal titration calorimetry) in combination with transgenic Arabidopsis lines were used to investigate the roles of these three ACBPs from Arabidopsis thaliana. The dissociation constants, stoichiometry and enthalpy change of AtACBP interactions with various acyl-CoA esters were determined using ITC. Strong binding of recombinant (r) AtACBP6 with long-chain acyl-CoA (C16- to C18-CoA) esters was observed with dissociation constants in the nanomolar range. However, the affinity of rAtACBP4 and rAtACBP5 to these acyl-CoA esters was much weaker (dissociation constants in the micromolar range), suggesting that they interact with acyl-CoA esters differently from rAtACBP6. When transgenic Arabidopsis expressing AtACBP6pro::GUS was generated, strong GUS (β-glucuronidase) expression in cotyledonary-staged embryos and seedlings prompted us to measure the acyl-CoA contents of the acbp6 mutant. This mutant accumulated higher levels of C18:1-CoA and C18:1- and C18:2-CoAs in cotyledonary-staged embryos and seedlings, respectively, in comparison with the wild type. The acbp4acbp5acbp6 mutant showed the lightest seed weight and highest sensitivity to abscisic acid during germination, suggesting their physiological functions in seeds.

Year of Publication2014
JournalBioscience Reports
Journal citation34 (6), pp. 865-877
Digital Object Identifier (DOI)doi:10.1042/BSR20140139
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Rothamsted Research
Funder project or codeDirectors Award
Designing Seeds for Nutrition and Health (DS)
Project: 6069
*Design Oilseeds (Olga Sayanova)
Publisher's version
Output statusPublished
Publication dates
Online01 Dec 2014
Publication process dates
Accepted01 Oct 2014
Copyright licenseCC BY
PublisherPortland Press Ltd
ISSN0144-8463

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