title: RppH-dependent pyrophosphohydrolysis of mRNAs is regulated by direct interaction with DapF in Escherichia coli.
abstract: Similar to decapping of eukaryotic mRNAs, the RppH-catalyzed conversion of 5'-terminal triphosphate to monophosphate has recently been identified as the rate-limiting step for the degradation of a subset of mRNAs in Escherichia coli. However, the regulation of RppH pyrophosphohydrolase activity is not well understood. Because the overexpression of RppH alone does not affect the decay rate of most target mRNAs, the existence of a mechanism regulating its activity has been suggested. In this study, we identified DapF, a diaminopimelate (DAP) epimerase catalyzing the stereoinversion of L,L-DAP to meso-DAP, as a regulator of RppH. DapF showed a high affinity interaction with RppH and increased its RNA pyrophosphohydrolase activity. The simultaneous overexpression of both DapF and RppH increased the decay rates of RppH target RNAs by about a factor of two. Together, our data suggest that the cellular level of DapF is a critical factor regulating the RppH-catalyzed pyrophosphate removal and the subsequent degradation of target mRNAs.
authors.affiliation: Department of Biological Sciences, Myongji University, Yongin, Gyeonggido 449-728, Republic of Korea.
authors.forename: Chang-Ro
authors.initials: CR
authors.lastname: Lee
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea.
authors.forename: Miri
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea.
authors.forename: Young-Ha
authors.initials: YH
authors.lastname: Park
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea.
authors.forename: Yeon-Ran
authors.initials: YR
authors.lastname: Kim
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea Department of Biophysics and Chemical Biology, Seoul National University, Seoul 151-742, Korea yjseok@snu.ac.kr.
authors.forename: Yeong-Jae
authors.initials: YJ
authors.lastname: Seok
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000378:metabolism*; D000591:Amino Acid Isomerases / Q000378:metabolism*; D011756:Diphosphates / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D006868:Hydrolysis; D033902:Periplasmic Binding Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*
chemical_list: D011756:Diphosphates; D029968:Escherichia coli Proteins; D033902:Periplasmic Binding Proteins; D012333:RNA, Messenger; C074783:osmY protein, E coli; D017766:Acid Anhydride Hydrolases; C526730:RppH protein, E coli; D000591:Amino Acid Isomerases; C042032:diaminopimelate epimerase