title: Farnesylcysteine lyase is involved in negative regulation of abscisic acid signaling in Arabidopsis.
abstract: The Arabidopsis FCLY gene encodes a specific farnesylcysteine (FC) lyase, which is responsible for the oxidative metabolism of FC to farnesal and cysteine. In addition, fcly mutants with quantitative decreases in FC lyase activity exhibit an enhanced response to ABA. However, the enzymological properties of the FCLY-encoded enzyme and its precise role in ABA signaling remain unclear. Here, we show that recombinant Arabidopsis FC lyase expressed in insect cells exhibits high selectivity for FC as a substrate and requires FAD and molecular oxygen for activity. Arabidopsis FC lyase is also shown to undergo post-translational N-glycosylation. FC, which is a competitive inhibitor of isoprenylcysteine methyltransferase (ICMT), accumulates in fcly mutants. Moreover, the enhanced response of fcly mutants to ABA is reversed by ICMT overexpression. These observations support the hypothesis that the ABA hypersensitive phenotype of fcly plants is the result of FC accumulation and inhibition of ICMT.
authors.affiliation: Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Huizinga
authors.forename: Ryan
authors.initials: R
authors.lastname: Denton
authors.forename: Kelly G
authors.initials: KG
authors.lastname: Koehler
authors.forename: Ashley
authors.initials: A
authors.lastname: Tomasello
authors.forename: Lyndsay
authors.initials: L
authors.lastname: Wood
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Sen
authors.forename: Dring N
authors.initials: DN
authors.lastname: Crowell
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013437:Carbon-Sulfur Lyases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C057785:S-farnesylcysteine; D000040:Abscisic Acid; D013437:Carbon-Sulfur Lyases; C523450:farnesylcysteine lyase, Arabidopsis; D003545:Cysteine