Ste5 tethers multiple protein kinases in the MAP kinase cascade required for mating in S. cerevisiae

Kang Yell Chol, Brett Satterberg, David M. Lyons, Elaine A. Elion

Research output: Contribution to journalArticle

413 Citations (Scopus)

Abstract

Ste5 is a Zn2+ finger-like protein thought to function before three kinases, Ste11 (a MEKK), Ste7 (a MEK), and Fus3 (a MAPK), in a conserved MAP kinase cascade required for mating in S. cerevisiae. Here, we present evidence that Ste5 forms a multikinase complex that joins these kinases for efficient Fus3 activation. By two-hybrid analysis, Ste11, Ste7, and Fus3 associate with different domains of Ste5, while Kss1, another MAPK, associates with the same domain as Fus3, thus implying that Ste5 simultaneously binds a MEKK, MEK, and MAPK. Ste5 copurifies with Ste11, Fus3, and a hypophosphorylated form of Ste7, and all four proteins cosediment in a glycerol gradient as if in a large complex. Ste5 also increases the amount of Ste11 complexed to Ste7 and Fus3 and is required for Ste11 to function. These results substantiate a novel signal transduction component that physically links multiple kinases within a single cascade.

Original languageEnglish
Pages (from-to)499-512
Number of pages14
JournalCell
Volume78
Issue number3
DOIs
Publication statusPublished - 1994 Aug 12

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)

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