title: The G-patch protein Spp2 couples the spliceosome-stimulated ATPase activity of the DEAH-box protein Prp2 to catalytic activation of the spliceosome.
abstract: Structural rearrangement of the activated spliceosome (B(act)) to yield a catalytically active complex (B*) is mediated by the DEAH-box NTPase Prp2 in cooperation with the G-patch protein Spp2. However, how the energy of ATP hydrolysis by Prp2 is coupled to mechanical work and what role Spp2 plays in this process are unclear. Using a purified splicing system, we demonstrate that Spp2 is not required to recruit Prp2 to its bona fide binding site in the B(act) spliceosome. In the absence of Spp2, the B(act) spliceosome efficiently triggers Prp2's NTPase activity, but NTP hydrolysis is not coupled to ribonucleoprotein (RNP) rearrangements leading to catalytic activation of the spliceosome. Transformation of the B(act) to the B* spliceosome occurs only when Spp2 is present and is accompanied by dissociation of Prp2 and a reduction in its NTPase activity. In the absence of spliceosomes, Spp2 enhances Prp2's RNA-dependent ATPase activity without affecting its RNA affinity. Our data suggest that Spp2 plays a major role in coupling Prp2's ATPase activity to remodeling of the spliceosome into a catalytically active machine.
authors.affiliation: Department of Cellular Biochemistry.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Warkocki
authors.affiliation: Department of Cellular Biochemistry.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Schneider
authors.affiliation: Department of Cellular Biochemistry.
authors.forename: Sina
authors.initials: S
authors.lastname: Mozaffari-Jovin
authors.affiliation: Department of Cellular Biochemistry.
authors.forename: Jana
authors.initials: J
authors.lastname: Schmitzová
authors.affiliation: Research Group of Nucleic Acid Chemistry, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Höbartner
authors.affiliation: Department of Cellular Biochemistry, reinhard.luehrmann@mpibpc.mpg.de patrizia.fabrizio@mpibpc.mpg.de.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Fabrizio
authors.affiliation: Department of Cellular Biochemistry.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lührmann
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D002384:Catalysis; D003067:Coenzymes / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D004789:Enzyme Activation; D006868:Hydrolysis; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D017381:Spliceosomes / Q000378:metabolism*
chemical_list: D003067:Coenzymes; C096994:SPP2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; C066490:PRP2 protein, S cerevisiae; D053487:DEAD-box RNA Helicases
keywords: ATP hydrolysis; DEAH-box helicase; G-patch protein; Prp2; Spp2; spliceosome activation