title: Crystal structure of the human Tip41 orthologue, TIPRL, reveals a novel fold and a binding site for the PP2Ac C-terminus.
abstract: TOR signaling pathway regulator-like (TIPRL) is a regulatory protein which inhibits the catalytic subunits of Type 2A phosphatases. Several cellular contexts have been proposed for TIPRL, such as regulation of mTOR signaling, inhibition of apoptosis and biogenesis and recycling of PP2A, however, the underlying molecular mechanism is still poorly understood. We have solved the crystal structure of human TIPRL at 2.15 Å resolution. The structure is a novel fold organized around a central core of antiparallel beta-sheet, showing an N-terminal α/β region at one of its surfaces and a conserved cleft at the opposite surface. Inside this cleft, we found a peptide derived from TEV-mediated cleavage of the affinity tag. We show by mutagenesis, pulldown and hydrogen/deuterium exchange mass spectrometry that this peptide is a mimic for the conserved C-terminal tail of PP2A, an important region of the phosphatase which regulates holoenzyme assembly, and TIPRL preferentially binds the unmodified version of the PP2A-tail mimetic peptide DYFL compared to its tyrosine-phosphorylated version. A docking model of the TIPRL-PP2Ac complex suggests that TIPRL blocks the phosphatase's active site, providing a structural framework for the function of TIPRL in PP2A inhibition.
authors.affiliation: Institute of Chemistry, University of Campinas, Campinas, São Paulo 13083-970, Brazil.|Brazilian National Laboratory for Biosciences, Center for Research in Energy and Materials, Campinas, São Paulo 13084-971, Brazil.|Institute of Biology, University of Campinas, Campinas, São Paulo 13083-970, Brazil.
authors.forename: Valéria
authors.initials: V
authors.lastname: Scorsato
authors.affiliation: Institute of Chemistry, University of Campinas, Campinas, São Paulo 13083-970, Brazil.|Brazilian National Laboratory for Biosciences, Center for Research in Energy and Materials, Campinas, São Paulo 13084-971, Brazil.
authors.forename: Tatiani B
authors.initials: TB
authors.lastname: Lima
authors.affiliation: Brazilian National Laboratory for Biosciences, Center for Research in Energy and Materials, Campinas, São Paulo 13084-971, Brazil.
authors.forename: Germanna L
authors.initials: GL
authors.lastname: Righetto
authors.affiliation: Carlos Chagas Insitute, Oswaldo Cruz Foundation (FIOCRUZ), Curitiba, P.R., Brazil.
authors.forename: Nilson I T
authors.initials: NI
authors.lastname: Zanchin
authors.affiliation: Diamond Light Source, OX11 0DE, Chilton, UK.
authors.forename: José
authors.initials: J
authors.lastname: Brandão-Neto
authors.affiliation: Diamond Light Source, OX11 0DE, Chilton, UK.
authors.forename: James
authors.initials: J
authors.lastname: Sandy
authors.affiliation: Physics Institute of São Carlos, University of São Paulo, São Carlos, São Paulo 13563-120, Brazil.
authors.forename: Humberto D'Muniz
authors.initials: HD
authors.lastname: Pereira
authors.affiliation: Institute of Chemistry, University of Campinas, Campinas, São Paulo 13083-970, Brazil.
authors.forename: Állan J R
authors.initials: ÁJ
authors.lastname: Ferrari
authors.affiliation: Institute of Chemistry, University of Campinas, Campinas, São Paulo 13083-970, Brazil.
authors.forename: Fabio C
authors.initials: FC
authors.lastname: Gozzo
authors.affiliation: Brazilian National Laboratory for Biosciences, Center for Research in Energy and Materials, Campinas, São Paulo 13084-971, Brazil.
authors.forename: Juliana H C
authors.initials: JH
authors.lastname: Smetana
authors.affiliation: Institute of Chemistry, University of Campinas, Campinas, São Paulo 13083-970, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Aparicio
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000502:physiology; D020134:Catalytic Domain / Q000502:physiology; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism*; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D010766:Phosphorylation / Q000502:physiology; D011485:Protein Binding / Q000235:genetics; D017510:Protein Folding; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D017433:Protein Structure, Secondary
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C577326:TIPRL protein, human; C517189:PPP2CA protein, human; D054648:Protein Phosphatase 2