Farnesylcysteine Lyase Regulation of Abscisic Arabidopsis is Involved in Negative Acid Signaling in  

作　　者：David H. Huizinga Ryan Denton Kelly G. Koehler Ashley Tomasello Lyndsay Wood Stephanie E. Sen Dring N. Crowell 

机构地区：[1]Department of Biology, Indiana University-Purdue University Indianapolis, 723 West Michigan Street, Indianapolis, IN 46202, USA [2]Department of Chemistry, Indiana University-Purdue University Indianapolis, 402 N. Blackford Street, Indianapolis, IN 46202, USA [3]Department of Chemistry, The College of New Jersey, 2000 Pennington Road, Ewing, NJ 08628, USA [4]Department of Biological Sciences, Idaho State University, 650 Memorial Drive, Pocatello, ID 83209, USA

出　　处：《Molecular Plant》2010年第1期143-155,共13页分子植物（英文版）

摘　　要：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 exhib- its 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 ICMToverexpression. These observations support the hypothesis that the ABA hypersensitive phenotype of fcly plants is the result of FC accumulation and inhibition of ICMT.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 exhib- its 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 ICMToverexpression. These observations support the hypothesis that the ABA hypersensitive phenotype of fcly plants is the result of FC accumulation and inhibition of ICMT.

关 键 词：Hormone biology primary metabolism seed biology STOMATA membrane proteins Arabidopsis. 

分 类 号：Q943[生物学—植物学] TS143.32[轻工技术与工程—纺织材料与纺织品设计]