title: The N-end rule pathway as a nitric oxide sensor controlling the levels of multiple regulators.
abstract: The conjugation of arginine to proteins is a part of the N-end rule pathway of protein degradation. Three amino (N)-terminal residues--aspartate, glutamate and cysteine--are arginylated by ATE1-encoded arginyl-transferases. Here we report that oxidation of N-terminal cysteine is essential for its arginylation. The in vivo oxidation of N-terminal cysteine, before its arginylation, is shown to require nitric oxide. We reconstituted this process in vitro as well. The levels of regulatory proteins bearing N-terminal cysteine, such as RGS4, RGS5 and RGS16, are greatly increased in mouse ATE1-/- embryos, which lack arginylation. Stabilization of these proteins, the first physiological substrates of mammalian N-end rule pathway, may underlie cardiovascular defects in ATE1-/- embryos. Our findings identify the N-end rule pathway as a new nitric oxide sensor that functions through its ability to destroy specific regulatory proteins bearing N-terminal cysteine, at rates controlled by nitric oxide and apparently by oxygen as well.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Rong-Gui
authors.initials: RG
authors.lastname: Hu
authors.forename: Jun
authors.initials: J
authors.lastname: Sheng
authors.forename: Xin
authors.initials: X
authors.lastname: Qi
authors.forename: Zhenming
authors.initials: Z
authors.lastname: Xu
authors.forename: Terry T
authors.initials: TT
authors.lastname: Takahashi
authors.forename: Alexander
authors.initials: A
authors.lastname: Varshavsky
mesh_terms: D019881:Aminoacyltransferases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000378:metabolism*; D018376:Cardiovascular Abnormalities / Q000235:genetics / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D020710:RGS Proteins / Q000378:metabolism
chemical_list: D005136:Eye Proteins; D020710:RGS Proteins; C107413:RGS16 protein; C105346:Rgs5 protein, mouse; C098799:RGS4 protein; D009569:Nitric Oxide; D001120:Arginine; D019881:Aminoacyltransferases; C019727:arginyltransferase; D003545:Cysteine; D010100:Oxygen