Journal
PLANT MOLECULAR BIOLOGY
Volume 90, Issue 4-5, Pages 453-466Publisher
SPRINGER
DOI: 10.1007/s11103-016-0429-z
Keywords
Metal P-type ATPase; Metal binding domain; Zinc transport; Structure-function analysis; Arabidopsis
Categories
Funding
- Fonds de la Recherche Scientifique-FNRS'' [FRFC-2.4583.08, PDR-T.0206.13]
- University of Liege [SFRD-12/03]
- Belgian Program on Interuniversity Poles of Attraction (IAP) [P6/19]
- Australian Research Council [DP130100728]
- FNRS
- Fonds pour la formation a la Recherche dans l'Industrie et dans l'Agriculture''
Ask authors/readers for more resources
P-IB 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 P-IB 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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available