Download MendeleyMechanism for Aar2p function as a U5 snRNP assembly factor.
Weber, G., Cristao, V.F., de L Alves, F., Santos, K.F., Holton, N., Rappsilber, J., Beggs, J.D., Wahl, M.C.(2011) Genes Dev 25: 1601-1612
- PubMed: 21764848
- DOI: https://doi.org/10.1101/gad.635911
- Primary Citation of Related Structures:
3SBG, 3SBS, 3SBT - PubMed Abstract:
Little is known about how particle-specific proteins are assembled on spliceosomal small nuclear ribonucleoproteins (snRNPs). Brr2p is a U5 snRNP-specific RNA helicase required for spliceosome catalytic activation and disassembly. In yeast, the Aar2 protein is part of a cytoplasmic precursor U5 snRNP that lacks Brr2p and is replaced by Brr2p in the nucleus. Here we show that Aar2p and Brr2p bind to different domains in the C-terminal region of Prp8p; Aar2p interacts with the RNaseH domain, whereas Brr2p interacts with the Jab1/MPN domain. These domains are connected by a long, flexible linker, but the Aar2p-RNaseH complex sequesters the Jab1/MPN domain, thereby preventing binding by Brr2p. Aar2p is phosphorylated in vivo, and a phospho-mimetic S253E mutation in Aar2p leads to disruption of the Aar2p-Prp8p complex in favor of the Brr2p-Prp8p complex. We propose a model in which Aar2p acts as a phosphorylation-controlled U5 snRNP assembly factor that regulates the incorporation of the particle-specific Brr2p. The purpose of this regulation may be to safeguard against nonspecific RNA binding to Prp8p and/or premature activation of Brr2p activity.
Organizational Affiliation:
Fachbereich Biologie/Chemie/Pharmazie, Abteilung Strukturbiochemie, Freie Universität Berlin, D-14195 Berlin, Germany;
