RalA GTPase associates with a phospholipase D (PLD) that is activated in v-Src- and v-Ras-transformed cells. Two mammalian PLDs were recently cloned: PLD1, which is activated by Arf family GTPases and dependent upon phosphatidylinositol-4,5-bisphosphate (PIP2), and PLD2, which is also dependent upon PIPE, but not stimulated by Arf. Another PLD has been described that is stimulated by oleate. Evidence is provided that the RalA-assiciated PLD is PLD1. First, the PLD precipitated by RalA from murine fibroblasts was stimulated by Arf, dependent upon PIP2, and inhibited by oleate. Second, immobilized RalA precipitated PLD1 from sf9 insect cells overexpressing PLD1. Third, a series of RalA mutants precipitated PLD activity from both PLD1-expressing insect cells and murine fibroblasts with the same efficiency. And finally, immobilized RalA precipitated PLD1 from a purified PLD1 preparation. These data argue that RalA associates directly with the Arf-responsive, PIP2-dependent PLD1.
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jun 27 1997|
Bibliographical noteFunding Information:
We are thankful to Paul Sternweis and Alex Brown for providing partially puri®ed native Arf protein. This investigation was supported by National Institutes of Health Grant CA46677, Council for Tobacco Research Grant 3075, American Cancer Society Grant BE-243 (to D.A.F.); a Research Centers in Minority Institutions award from the Division of Research Resources, National Institutes of Health (RR 03037) to Hunter College; National Institutes of Health Grant GM47707 and an American Cancer Society faculty research award (to L.A.F.); National Institutes of Health Grants GM50388 (to A.J.M.) and HD29758 (to M.A.F.). S.M.H. is a Pharmaceutical Manufacturers Foundation Predoctoral Fellow. X.L. was a Howard Hughes Medical Institute Undergraduate Scholar.
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology