Stt4 PI 4-kinase localizes to the plasma membrane and functions in the Pkc1-mediated MAP kinase cascade

Dev Cell. 2002 May;2(5):593-605. doi: 10.1016/s1534-5807(02)00168-5.


Production of the essential phospholipid PI4P at the Golgi by the Pik1 kinase is required for protein secretion, while a distinct pool of PI4P generated by the Stt4 kinase is critical for normal actin cytoskeleton organization. We identify a transmembrane protein that stabilizes Stt4 at the plasma membrane where it directs synthesis of PI4P, which is required for activation of the Rho1/Pkc1-mediated MAP kinase cascade. Inactivation of Stt4 or the PI4P 5-kinase Mss4 results in mislocalization of the Rho-GTPase GEF Rom2. Rom2 binds PI4,5P(2) through its PH domain and represents the first identified effector in the Stt4-Mss4 pathway. Based on these results, we propose that Stt4-Mss4 generates PI4,5P(2) at the plasma membrane, required to recruit/activate effector proteins such as Rom2.

Publication types

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

MeSH terms

  • 1-Phosphatidylinositol 4-Kinase / genetics
  • 1-Phosphatidylinositol 4-Kinase / metabolism*
  • Cell Membrane / metabolism
  • Enzyme Activation
  • Fungal Proteins / metabolism*
  • Genes, Fungal
  • Genes, Suppressor
  • Mitogen-Activated Protein Kinases / metabolism*
  • Models, Biological
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositol Phosphates / metabolism
  • Phosphotransferases (Alcohol Group Acceptor)
  • Phosphotransferases*
  • Protein Kinase C
  • Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism


  • Fungal Proteins
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositol Phosphates
  • Proteins
  • Saccharomyces cerevisiae Proteins
  • phosphatidylinositol 4-phosphate
  • Phosphotransferases
  • Phosphotransferases (Alcohol Group Acceptor)
  • Pkc1 protein, Trichoderma reesei
  • 1-Phosphatidylinositol 4-Kinase
  • PIK1 protein, S cerevisiae
  • STT4 protein, S cerevisiae
  • MSS4 protein, S cerevisiae
  • Protein Kinase C
  • Mitogen-Activated Protein Kinases