title: 1-Aminocyclopropane-1-carboxylic acid synthase 2 is phosphorylated by calcium-dependent protein kinase 1 during cotton fiber elongation.
abstract: The reaction catalyzed by 1-aminocyclopropane-1-carboxylic acid synthase (ACS) is proposed to be the rate-limiting step in ethylene biosynthesis, which has been found as one of the most up-regulated metabolic pathways during cotton fiber development. However, the transcripts of the identified ACS genes did not increase in a similar manner as those of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) genes, implicating a possible post-transcriptional modification or regulatory mechanism. In this work, cotton ACS2 was shown to interact with Ca(2+)-dependent protein kinase 1 (CPK1). Bacterially expressed and purified recombinant ACS2 was phosphorylated by CPK1 in vitro and site-directed mutagenesis studies suggest that ACS2 S460 is a possible phosphorylation site for CPK1. Phosphorylated ACS2 significantly increased ACS activity, leading to elevated ethylene production. We thus speculated that CPK1 is involved in cotton fiber growth regulation by phosphorylating ACS2, which results in enhanced ethylene production in vitro.
authors: The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China.
authors: Hui
authors: H
authors: Wang
authors: Wenqian
authors: W
authors: Mei
authors: Yongmei
authors: Y
authors: Qin
authors: Yuxian
authors: Y
authors: Zhu
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers; D005030:Ethylenes / Q000378:metabolism; D003368:Gossypium / Q000166:cytology / Q000201:enzymology*; D047468:Immunoprecipitation; D008190:Lyases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D012323:RNA Processing, Post-Transcriptional; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D005030:Ethylenes; C036216:ethylene; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase