Domain interactions within the Ski2/3/8 complex and between the Ski complex and Ski7p

RNA. 2005 Aug;11(8):1291-302. doi: 10.1261/rna.2060405.

Abstract

The Ski complex (composed of Ski3p, Ski8p, and the DEVH ATPase Ski2p) is a central component of the 3'-5' cytoplasmic mRNA degradation pathway in yeast. Although the proteins of the complex interact with each other as well as with Ski7p to mediate degradation by exosome, a 3'-exonuclease complex, the nature of these interactions is not well understood. Here we explore interactions within the Ski complex and between the Ski complex and Ski7p using a directed two-hybrid approach combined with coimmunoprecipitation experiments. We also test the functional significance of these interactions in vivo. Our results suggest that within the Ski complex, Ski3p serves as a scaffold protein with its C terminus interacting with Ski8p, and the sub-C terminus interacting with Ski2p, while no direct interaction between Ski2p and Ski8p was found. Ski7p interacts with the Ski complex via its interaction with Ski8p and Ski3p. In addition, inactivating the Ski complex by mutating conserved residues in the DEVH helicase motif of Ski2 did not abrogate its interaction with Ski7p, indicating that Ski2p function is not necessary for this interaction.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Binding Sites
  • Kinetics
  • Macromolecular Substances / chemistry
  • Macromolecular Substances / metabolism
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / metabolism*
  • Protein Conformation
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Macromolecular Substances
  • Nuclear Proteins
  • SKI2 protein, S cerevisiae
  • SKI3 protein, S cerevisiae
  • SKI7 protein, S cerevisiae
  • SKI8 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins