Ypp1 functions in the PtdIns4P signaling pathway to positively regulate Stt4 kinase activity. (A) The relative growth capabilities of wild type, stt4-4, and ypp1-7 at 26 (top left) and 37°C (bottom left). The relative growth capability of ypp1-7 with overexpression of YPP1 from a 2μ plasmid, plasmid alone (pRS426), or overexpressed STT4 at 37°C (top right). Similar growth profile of stt4-4 at 37°C in the presence of vector alone or in the presence of overexpressed YPP1 (bottom right). (B) Whole cell lysate from teto-YPP1-HA cells grown in the presence or absence of doxycycline were analyzed by Western blot with an anti-HA antibody. The relative abundance of Ypp1-HA under the indicated conditions (top) and the relative abundance of a control protein, G6PDH, from the same lysate (bottom) are shown. (C) Phosphoinositide levels in teto-YPP1 cells with and without doxycycline and control R1158 in the presence of doxycycline. Data are presented as means and SD (error bars) of three independent experiments.
