The roles of selectivity filters in determining aluminum transport by AtNIP1;2

Yuqi Wang; Enzong Xiao; Guorong Wu; Qing Bai; Feng Xu; Xiyue Ji; Chune Li; Li Li; Jiping Liu

doi:10.1080/15592324.2021.1991686

The roles of selectivity filters in determining aluminum transport by AtNIP1;2

Plant Signal Behav. 2021 Dec 2;16(12):1991686. doi: 10.1080/15592324.2021.1991686. Epub 2021 Oct 28.

Authors

Yuqi Wang^{1

2}, Enzong Xiao¹, Guorong Wu¹, Qing Bai¹, Feng Xu¹, Xiyue Ji¹, Chune Li¹, Li Li^{2

3}, Jiping Liu^{2

3}

Affiliations

¹ Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China.
² Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA.
³ Plant Breeding and Genetics Section, School of Integrative Plant Sciences, Cornell University, Ithaca, Ny, USA.

Abstract

Aquaporins (AQPs) are channel proteins involved in transporting a variety of substrates. It has been proposed that the constriction regions in the central pores of the AQP channels play a crucial role in determining transport substrates and activities of AQPs. Our previous results suggest that AtNIP1;2, a member of the AQP superfamily in Arabidopsis, facilitates aluminum transport across the plasma membrane. However, the functions of the constriction regions in AtNIP1;2-mediated transport activities are unclear. This study reports that residue substitutions of the constriction regions affect AtNIP1;2-mediated aluminum uptake, demonstrating the critical roles of the constriction regions for transport activities. Furthermore, a constriction region that partially or wholly mimics AtNIP5;1, a demonstrated boric-acid transporter, could not render the boric-acid transport activity to AtNIP1;2. Therefore, besides the constriction regions, other structural features are also involved in determining the nature of AtNIP1;2's transport activities.Abbreviations: AIAR: alanine-isoleucine-alanine-arginine; AIGR: alanine-isoleucine-glycine- arginine; AQP: aquaporin; Al-Mal: aluminum-malate; ar/R: aromatic/arginine; AVAR: alanine-valine-alanine-arginine; CK: control; H: helical domain; ICP-MS: inductively coupled plasma mass spectrometry; LA - LE: inter-helical loops A to E; NIP: nodulin 26-like intrinsic protein; NPA: asparagine-proline-alanine; NPG: asparagine-proline- glycine; NPS: asparagine-proline-Serine; NPV: asparagine-proline-valine; ORF: open reading frame; PIP: plasma membrane intrinsic proteins; SIP: small basic intrinsic proteins; TM: transmembrane helices; WIAR: tryptophan-isoleucine-alanine-arginine; WVAR: tryptophan-valine-alanine-arginine; WVGR: tryptophan-valine-glycine- arginine.

Keywords: Aluminum tolerance; NPA motifs; aquaporin; ar/R selectivity filter; nodulin 26-like intrinsic protein.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aluminum
Aquaporins* / metabolism
Arabidopsis Proteins* / metabolism
Arabidopsis* / metabolism
Arginine / metabolism
Isoleucine

Substances

Aquaporins
Arabidopsis Proteins
NIP1-2 protein, Arabidopsis
Isoleucine
Arginine
Aluminum

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China (41877423), Guangzhou Science and Technology Project (202102010385), and Rural Revitalization Strategy Project from the Department of Science and Technology of Guangdong Province (620096-3) to Y.W. and by a USDA-ARS base fund to J.L.