Protein–protein interactions in fatty acid elongase complexes are important for very-long-chain fatty acid synthesis

Abstract

Fatty acid elongase (FAE), which catalyzes the synthesis of very-long-chain fatty acids (VLCFAs), is a multiprotein complex; however, little is known about its quaternary structure. In this study, BiFC and/or yeast two hybrid (Y2H) assays showed that 1) homo-interactions were observed in β-ketoacyl-CoA synthases (KCS2, KCS9, and KCS6), Eceriferum2-like proteins [CER2 and CER2-Like2 (C2L2)], and FAE complex proteins (KCR1, PAS2, ECR, and PAS1), except for CER2-Like1 (C2L1). 2) Hetero-interactions were observed between KCSs (KCS2, KCS9, and KCS6), between CER2-LIKEs (CER2, C2L2, and C2L1), and between FAE complex proteins (KCR1, PAS2, ECR, and PAS1). 3) PAS1 interacts with FAE complex proteins (KCR1, PAS2, and ECR), but not with KCSs (KCS2, KCS9, and KCS6) and CER2-LIKEs (CER2, C2L2, and C2L1). 4) Asp (308 aa) and three Arg (309 to 311 aa) residues of KCS9 were essential for the homo-interactions of KCS9 and hetero-interactions between KCS9 and PAS2 or ECR. An Asp (339 aa) residue of KCS9 is involved in its homo- and hetero-interactions with ECR. Complementation analysis of Arabidopsis kcs9 mutant by the expression of amino acid-substituted KCS9 mutant genes showed that 5) Two Asp residues (308 and 339 aa) of KCS9 are involved in the synthesis of C24 VLCFAs from C22. This study suggests that protein-protein interaction (PPI) in FAE complexes is important for VLCFA synthesis and provides insight into the quaternary structure of FAE complexes for efficient synthesis of VLCFAs.

DsCER26 Affects the Leaf Dehydration Tolerance of Rice by Altering Cuticular Wax Alkane Production without Affecting the Grain Fatty Acid Content

“…An additional family of the AtCER2-like proteins (including AtCER2, AtCER2-like1/CER26, and AtCER2-like2/CER26-like) belong to the BAHD acyltransferase family (named for the first four enzymes described in this clade: benzylalcohol O -acetyltransferase, anthocyanin O -hydroxycinnamoyltransferase, N -hydroxycinnamoyl/benzoyltransferase, and deacetylvindoline 4- O -acetyltransferase) and are considered to be involved in the synthesis of VLCFAs longer than C28 as they interact specifically with AtKCS6/CER6 or AtKCS5/CER60. ,− Recently, bimolecular fluorescence complementation analysis has shown that AtCER2-like proteins directly interact with AtKCS6/CER6 . In addition to Arabidopsis, OsCER2-like/CER26 and OsKCS6/CER6 genes from rice have been identified and characterized.…”

“…Previous research has revealed that they are all localized to the ER and catalyze the biosynthesis of VLCFAs beyond C26 by interacting with KCS6. However, they exhibit different organ expression specificity and substrate specificity. ,,, AtCER2 is expressed in almost all aerial organs, and its mutation causes a significant reduction of multiple C29 wax monomers on Arabidopsis stems, including the C29 alkane, C29 ketone, and the C29 secondary alcohol , Since AtCER26L is mainly expressed in anthers, its mutation does not cause changes in the wax composition on the Arabidopsis rosette leaves.…”

Toward a smart skin: Harnessing cuticle biosynthesis for crop adaptation to drought, salinity, temperature, and ultraviolet stress

“…For the cuticular wax biosynthesis, plastid-derived C16 and C18 acyl-CoAs were first elongated to VLC (up to C34) acyl-CoAs by the FAE complex and the ECERIFERUM2 (CER2) protein ( Haslam et al, 2015 ). It was recently demonstrated that protein-protein interactions in the FAE complex, including extensive protein–protein interactions among Arabidopsis FAE complex proteins KCR1, PASTICCINO2 (PAS2), ECR, and PAS1, as well as specific interactions between KCS9 and PAS2 or ECR, are essential to the VLC acyl-CoAs elongation ( Kim et al, 2021 ). These elongated VLC acyl-CoAs were then either converted into n -alkanes, n -aldehydes, secondary alcohols, and ketones via the alkane-forming pathway or modified into primary n -alcohols and esters through the alcohol-forming pathway.…”

ELO2 Participates in the Regulation of Osmotic Stress Response by Modulating Nitric Oxide Accumulation in Arabidopsis

“…VLCFAs, as hydrocarbon chains containing more than 20 carbon atoms, are the precursors of different kinds of lipids such as phospholipids and sphingolipids, and function in various physiological processes (Bach et al, 2011 ; Wang et al, 2018 ; Zhukov, 2018 ; Kim et al, 2021 ). Elo1, Elo2, and Elo3 are three fatty acid elongases in yeast.…”