Biopolis Dresden Imaging Platform

Interaction between Sec7p and Pik1p: the first clue for the regulation of a coincidence detection signal.

Gloor Y, Schöne M, Habermann B, Ercan E, Beck M, Weselek G, Müller-Reichert T, Walch-Solimena C

Sec7p, a guanine nucleotide exchange factor, regulates the activation of small Arf GTPases, which function in the formation of distinct classes of transport carriers from the Golgi. The recruitment of a subset of Arf effectors depends on the cooperation between these GTPases and phosphatidylinositol 4-phosphate. Here, we show that the catalytic domain of Sec7p interacts with a conserved region of the Golgi phosphatidylinositol 4-kinase Pik1p. We found that Sec7p and Pik1p as well as its product, colocalize at the late Golgi. Gea1p/Gea2p, an alternative pair of Arf activators, do not bind to Pik1p and function on a different Golgi sub-compartment. Sec7p and Pik1p interact with each other and cooperate in the formation of clathrin-coated vesicles. This interaction reveals a distinct role for Sec7p among the Golgi Arf-GEFs and provides a working model for the coordinated generation of Arf-GTP and phosphatiylinositol 4-phosphate as dual signal for specific recruitment of clathrin coats to the late Golgi.

Fig.3 taken from Gloor et al, 2010.
  • Eur. J. Cell Biol. 2010 Aug;89(8):575-83
  • 2010
  • Cell Biology
  • 20434792
  • PubMed
Back to list