Plant Molecular Biology

, Volume 60, Issue 5, pp 729–746

The Highly Charged Region of Plant β-type Phosphatidylinositol 4-kinase is Involved in Membrane Targeting and Phospholipid Binding

  • Ying Lou
  • Hui Ma
  • Wen-Hui Lin
  • Zhao-Qing Chu
  • Bernd Mueller-Roeber
  • Zhi-Hong Xu
  • Hong-Wei Xue
Article

DOI: 10.1007/s11103-005-5548-x

Cite this article as:
Lou, Y., Ma, H., Lin, W. et al. Plant Mol Biol (2006) 60: 729. doi:10.1007/s11103-005-5548-x

Abstract

In Arabidopsis thaliana and Oryza sativa, two types of PI 4-kinase (PI4Ks) have been isolated and functionally characterized. The α-type PI4Ks (~220 kDa) contain a PH domain, which is lacking in β-type PI4Ks (~120 kDa). β-Type PI4Ks, exemplified by Arabidopsis AtPI4Kβ and rice OsPI4K2, contain a highly charged repetitive segment designated PPC (Plant PI4K Charged) region, which is an unique domain only found in plant β-type PI4Ks at present. The PPC region has a length of ~300 amino acids and harboring 11 (AtPI4Kβ) and 14 (OsPI4K2) repeats, respectively, of a 20-aa motif. Studies employing a modified yeast-based “Sequence of Membrane-Targeting Detection” system demonstrate that the PPC(OsPI4K2) region, as well as the former 8 and latter 6 repetitive motifs within the PPC region, are able to target fusion proteins to the plasma membrane. Further detection on the transiently expressed GFP fusion proteins in onion epidermal cells showed that the PPC(OsPI4K2) region alone, as well as the region containing repetitive motifs 1–8, was able to direct GFP to the plasma membrane, while the regions containing less repetitive motifs, i.e. 6, 4, 2 or single motif(s) led to predominantly intracellular localization. Agrobacterium-mediated transient expression of PPC-GFP fusion protein further confirms the membrane-targeting capacities of PPC region. In addition, the predominant plasma membrane localization of AtPI4Kβ was mediated by the PPC region. Recombinant PPC peptide, expressed in E. coli, strongly binds phosphatidic acid, PI and PI4P, but not phosphatidylcholine, PI5P, or PI(4,5)P2in vitro, providing insights into potential mechanisms for regulating sub-cellular localization and lipid binding for the plant β-type PI4Ks.

Keywords

GFPmembrane targetingPI4KPPC (Plant PI4Ks Charged) regionsignal transductionyeast

Abbreviations

PI

phosphatidylinositol

PI4P

PI 4-monophosphate

PI5P

PI 5-monophosphate

PI(4,5)P2

PI 4,5-bisphosphate

PI4K

PI 4-kinase

PA

phosphatidic acid

PAGE

polyacrylamide gel electrophoresis

Copyright information

© Springer 2006

Authors and Affiliations

  • Ying Lou
    • 1
  • Hui Ma
    • 1
    • 3
  • Wen-Hui Lin
    • 1
  • Zhao-Qing Chu
    • 1
    • 4
  • Bernd Mueller-Roeber
    • 2
  • Zhi-Hong Xu
    • 1
  • Hong-Wei Xue
    • 1
  1. 1.National Key Laboratory of Plant Molecular GeneticsInstitute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science (SiBS), Chinese Academy of Sciences; and Partner Group of Max–Planck-Institute of Molecular Plant Physiology (MPI-MP) on “Plant Molecular Physiology and Signal Transduction”ShanghaiP.R. China
  2. 2.Institute for Biochemistry and BiologyUniversity of PotsdamHaus 20Germany
  3. 3.ERRB, NICHD, Unit of Molecular Signal TransductionBethesdaUSA
  4. 4.Temasek Life Sciences Laboratory, 1 Research LinkThe National University of SingaporeSingapore