title: Arabidopsis C-terminal domain phosphatase-like 1 and 2 are essential Ser-5-specific C-terminal domain phosphatases.
abstract: Transcription and mRNA processing are regulated by phosphorylation and dephosphorylation of the C-terminal domain (CTD) of RNA polymerase II, which consists of tandem repeats of a Y(1)S(2)P(3)T(4)S(5)P(6)S(7) heptapeptide. Previous studies showed that members of the plant CTD phosphatase-like (CPL) protein family differentially regulate osmotic stress-responsive and abscisic acid-responsive transcription in Arabidopsis thaliana. Here we report that AtCPL1 and AtCPL2 specifically dephosphorylate Ser-5 of the CTD heptad in Arabidopsis RNA polymerase II, but not Ser-2. An N-terminal catalytic domain of CPL1, which suffices for CTD Ser-5 phosphatase activity in vitro, includes a signature DXDXT acylphosphatase motif, but lacks a breast cancer 1 CTD, which is an essential component of the fungal and metazoan Fcp1 CTD phosphatase enzymes. The CTD of CPL1, which contains two putative double-stranded RNA binding motifs, is essential for the in vivo function of CPL1 and includes a C-terminal 23-aa signal responsible for its nuclear targeting. CPL2 has a similar domain structure but contains only one double-stranded RNA binding motif. Combining mutant alleles of CPL1 and CPL2 causes synthetic lethality of the male but not the female gametes. These results indicate that CPL1 and CPL2 exemplify a unique family of CTD Ser-5-specific phosphatases with an essential role in plant growth and development.
authors.affiliation: Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843-2133, USA. koiwa@neo-tamu.edu
authors.forename: Hisashi
authors.initials: H
authors.lastname: Koiwa
authors.forename: Stéphane
authors.initials: S
authors.lastname: Hausmann
authors.forename: Woo Young
authors.initials: WY
authors.lastname: Bang
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ueda
authors.forename: Naoko
authors.initials: N
authors.lastname: Kondo
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hiraguri
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Fukuhara
authors.forename: Jeong Dong
authors.initials: JD
authors.lastname: Bahk
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
authors.forename: Ray A
authors.initials: RA
authors.lastname: Bressan
authors.forename: Paul M
authors.initials: PM
authors.lastname: Hasegawa
authors.forename: Stewart
authors.initials: S
authors.lastname: Shuman
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000201:enzymology; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D013379:Substrate Specificity; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D012694:Serine; D012319:RNA Polymerase II; C465438:CPL1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases