Skip to main content
Log in

Metal binding to the N-terminal cytoplasmic domain of the PIB ATPase HMA4 is required for metal transport in Arabidopsis

  • Published:
Plant Molecular Biology Aims and scope Submit manuscript

Abstract

PIB ATPases are metal cation pumps that transport metals across membranes. These proteins possess N- and C-terminal cytoplasmic extensions that contain Cys- and His-rich high affinity metal binding domains, which may be involved in metal sensing, metal ion selectivity and/or in regulation of the pump activity. The PIB ATPase HMA4 (Heavy Metal ATPase 4) plays a central role in metal homeostasis in Arabidopsis thaliana and has a key function in zinc and cadmium hypertolerance and hyperaccumulation in the extremophile plant species Arabidopsis halleri. Here, we examined the function and structure of the N-terminal cytoplasmic metal-binding domain of HMA4. We mutagenized a conserved CCTSE metal-binding motif in the domain and assessed the impact of the mutations on protein function and localization in planta, on metal-binding properties in vitro and on protein structure by Nuclear Magnetic Resonance spectroscopy. The two Cys residues of the motif are essential for the function, but not for localization, of HMA4 in planta, whereas the Glu residue is important but not essential. These residues also determine zinc coordination and affinity. Zinc binding to the N-terminal domain is thus crucial for HMA4 protein function, whereas it is not required to maintain the protein structure. Altogether, combining in vivo and in vitro approaches in our study provides insights towards the molecular understanding of metal transport and specificity of metal P-type ATPases.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+
from $39.99 /Month
  • Starting from 10 chapters or articles per month
  • Access and download chapters and articles from more than 300k books and 2,500 journals
  • Cancel anytime
View plans

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

Download references

Acknowledgments

We thank Dr. C. Nouet, S. Fanara, M. Schloesser and M.C. Requier for technical support. Prof. A. Wedd is thanked for his constructive comments and suggestions. We thank Dr. M. Haydon for the kind gift of hma2hma4 seeds. Funding was provided by the “Fonds de la Recherche Scientifique–FNRS” (FRFC-2.4583.08, PDR-T.0206.13) (MH, MG), the University of Liège (SFRD-12/03) (MH), the Belgian Program on Interuniversity Poles of Attraction (IAP no. P6/19) and the Australian Research Council (Grant DP130100728) (AAU, ZX). MH is Research Associate of the FNRS. Doctoral fellowships were funded by the FNRS (CL) and the “Fonds pour la formation à la Recherche dans l’Industrie et dans l’Agriculture” (GL, JBC).

Author contribution

MG and MH conceived and directed the study. MH, MG, CD and ZX designed experiments. CL, GL, JBC, BB, AAU, ZX and CD performed experiments. CL, MH, CD, GL, BB, AAU and ZX analysed the data. MH, MG, CD, AAU, ZX, PM and MC contributed reagents/materials/analysis tools. MH, CL and MG wrote the paper and all authors commented on the manuscript.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Marc Hanikenne.

Additional information

Clémentine Laurent and Gilles Lekeux have contributed equally to this work.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (PDF 465 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Laurent, C., Lekeux, G., Ukuwela, A.A. et al. Metal binding to the N-terminal cytoplasmic domain of the PIB ATPase HMA4 is required for metal transport in Arabidopsis . Plant Mol Biol 90, 453–466 (2016). https://doi.org/10.1007/s11103-016-0429-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11103-016-0429-z

Keywords