植物细胞(THE PLANT CELL)2013-09-05 2:57 AM

Allosteric Regulation of Transport Activity by Heterotrimerization of Arabidopsis Ammonium Transporter Complexes in Vivo

Ammonium acquisition by plant roots is mediated by AMMONIUM TRANSPORTERs (AMTs), ubiquitous membrane proteins with essential roles in nitrogen nutrition in all organisms. In microbial and plant cells, ammonium transport activity is controlled by ammonium-triggered feedback inhibition to prevent cellular ammonium toxicity. Data from heterologous expression in yeast indicate that oligomerization of plant AMTs is critical for allosteric regulation of transport activity, in which the conserved cytosolic C terminus functions as a trans-activator. Employing the coexpressed transporters AMT1;1 and AMT1;3 from Arabidopsis thaliana as a model, we show here that these two isoforms form functional homo- and heterotrimers in yeast and plant roots and that AMT1;3 carrying a phosphomimic residue in its C terminus regulates both homo- and heterotrimers in a dominant-negative fashion in vivo. 15NH4+ influx studies further indicate that allosteric inhibition represses ammonium transport activity in roots of transgenic Arabidopsis expressing a phosphomimic mutant together with functional AMT1;3 or AMT1;1. Our study demonstrates in planta a regulatory role in transport activity of heterooligomerization of transporter isoforms, which may enhance their versatility for signal exchange in response to environmental triggers.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

植物细胞(THE PLANT CELL)

0 Following 1 Fans 0 Projects 47 Articles

SIMILAR ARTICLES

BINDING PROTEIN (BiP) is a major chaperone in the endoplasmic reticulum (ER) lumen, and this study shows that BiP binds to the C-terminal tail of the s

Read More

Vesicle trafficking plays an important role in cell division, establishment of cell polarity, and translation of environmental cues to developmental re

Read More

The genus Brassica includes several important agricultural and horticultural crops. Their current genome structures were shaped by whole-genome triplic

Read More

Trans-acting small interfering RNAs (tasiRNAs) are a major class of small RNAs performing essential biological functions in plants. The first reported

Read More

RK5 is a member of the Arabidopsis thaliana Ca2+/calmodulin-dependent kinase-related kinase family. Here, we show that inactivation of CRK5 inhibits pr

Read More

The waxy plant cuticle protects cells from dehydration, repels pathogen attack, and prevents organ fusion during development. The transcription factor

Read More

Constrained to develop within the seed, the plant embryo must adapt its shape and size to fit the space available. Here, we demonstrate how this adjust

Read More

N-myristoylation is a crucial irreversible eukaryotic lipid modification allowing a key subset of proteins to be targeted at the periphery of specific

Read More

Exocysts are highly conserved octameric complexes that play an essential role in the tethering of Golgi-derived vesicles to target membranes in eukaryo

Read More

Apical actin filaments are crucial for pollen tube tip growth. However, the specific dynamic changes and regulatory mechanisms associated with actin fi

Read More