title: Self-catalyzed cleavage of the yeast nucleoporin Nup145p precursor.
abstract: Nup145p is a component of the nuclear pore complex of Saccharomyces cerevisiae and is essential for mRNA export. Nup145p and its apparent vertebrate homologue are the only known nucleoporins to be composed of two functionally independent peptide moieties resulting from the post-translational cleavage of a large precursor molecule. In this study, the proteolytic cleavage site of Nup145p has been mapped upstream of an evolutionary conserved serine residue. Cleavage occurs at the same site when a precursor is artificially expressed in Escherichia coli. A hydroxyl-containing residue is critical for the reaction, although a thiol-containing residue offers an acceptable replacement. In vitro kinetics experiments using a purified precursor molecule demonstrate that the cleavage is self-catalyzed and that the catalytic domain lies within the N-terminal moiety. Taken altogether, our data are consistent with a proteolytic mechanism involving an N>O acyl rearrangement and a subsequent ester intermediate uncovered in other self-processing proteins.
authors.affiliation: Unité de Génétique Moléculaire des levures, Institut Pasteur, Département des Biotechnologies, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France. teresatf@pasteur.fr
authors.forename: M T
authors.initials: MT
authors.lastname: Teixeira
authors.forename: E
authors.initials: E
authors.lastname: Fabre
authors.forename: B
authors.initials: B
authors.lastname: Dujon
mesh_terms: D002384:Catalysis; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D028861:Nuclear Pore Complex Proteins; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship
chemical_list: D005656:Fungal Proteins; C088627:NUP145 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D010446:Peptide Fragments; D011498:Protein Precursors; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins