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  • The EMBO Journal (2003) 22, 4059 - 4069
  • doi:10.1093/emboj/cdg390

Activation of phospholipase D by the small GTPase Sar1p is required to support COPII assembly and ER export

Purnima Pathre1, Kuntala Shome2, Anna Blumental-Perry1, Anna Bielli1, Charles J. Haney1, Sean Alber1, Simon C. Watkins1, Guillermo Romero2 and Meir Aridor1

  1. Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15261, USA
  2. Department of Pharmacology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15261, USA

Correspondence to:

Meir Aridor, E-mail: aridor+@pitt.edu

Received 19 November 2002; Accepted 17 June 2003; Revised 19 May 2003

The small GTPase Sar1p controls the assembly of the cytosolic COPII coat that mediates export from the endoplasmic reticulum (ER). Here we demonstrate that phospholipase D (PLD) activation is required to support COPII-mediated ER export. PLD activity by itself does not lead to the recruitment of COPII to the membranes or ER export. However, PLD activity is required to support Sar1p-dependent membrane tubulation, the subsequent Sar1p-dependent recruitment of Sec23/24 and Sec13/31 COPII complexes to ER export sites and ER export. Sar1p recruitment to the membrane is PLD independent, yet activation of Sar1p is required to stimulate PLD activity on ER membranes, thus PLD is temporally regulated to support ER export. Regulated modification of membrane lipid composition is required to support the cooperative interactions that enable selective transport, as we demonstrate here for the mammalian COPII coat.

  • Keywords:

    • COPII,
    • endoplasmic reticulum,
    • PLD,
    • Sar1p