Arabidopsis Rab-E GTPases exhibit a novel interaction with a plasma-membrane phosphatidylinositol-4-phosphate 5-kinase

Luisa Camacho, Andrei P. Smertenko, Jose Perez-Gomez, Patrick J. Hussey, Ian Moore*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)

Abstract

Rab GTPases of the Arabidopsis Rab-E subclass are related to mammalian Rab8 and are implicated in membrane trafficking from the Golgi to the plasma membrane. Using a yeast two-hybrid assay, Arabidopsis phosphatidylinositol-4-phosphate 5-kinase 2 (PtdIns(4)P 5-kinase 2; also known as PIP5K2), was shown to interact with all five members of the Rab-E subclass but not with other Rab subclasses residing at the Golgi or trans-Golgi network. Interactions in yeast and in vitro were strongest with RAB-E1d[Q74L] and weakest with the RAB-E1d[S29N] suggesting that PIP5K2 interacts with the GTP-bound form. PIP5K2 exhibited kinase activity towards phosphatidylinositol phosphates with a free 5-hydroxyl group, consistent with PtdIns(4)P 5-kinase activity and this activity was stimulated by Rab binding. Rab-E proteins interacted with PIP5K2 via its membrane occupancy and recognition nexus (MORN) domain which is missing from animal and fungal PtdIns(4)P 5-kinases. In plant cells, GFP:PIP5K2 accumulated at the plasma membrane and caused YFP:RAB-E1d to relocate there from its usual position at the Golgi. GFP:PIP5K2 was rapidly turned over by proteasomal activity in planta, and overexpression of YFP:PIP5K2 caused pleiotropic growth abnormalities in transgenic Arabidopsis. We propose that plant cells exhibit a novel interaction in which PIP5K2 binds GTP-bound Rab-E proteins, which may stimulate temporally or spatially localized PtdIns(4,5)P(2) production at the plasma membrane.

Original languageEnglish
Pages (from-to)4383-4392
Number of pages10
JournalJournal of Cell Science
Volume122
Issue number23
DOIs
Publication statusPublished - 01 Dec 2009

Keywords

  • MONOPHOSPHATE KINASE
  • BINDING PROTEINS
  • Secretion
  • 4,5-BISPHOSPHATE
  • Root hair
  • MG132
  • POLLEN-TUBE GROWTH
  • Proteasome
  • MORN domain
  • Ypt2
  • PtdIns(4,5)P(2)
  • ENDOPLASMIC-RETICULUM
  • GOLGI-APPARATUS
  • IN-VITRO
  • ORGANELLE IDENTITY
  • THALIANA
  • SACCHAROMYCES-CEREVISIAE

Cite this