Skip to main navigation Skip to main content
The University of Southampton
Biological Sciences

Research project: Are GTGs a new class of plant anion channels regulating pH in the endomembrane system?

Currently Active:

Given the significant sequence similarity between members of the GTG/GPHR family, we are testing whether the GTG/GPHR family has a conserved physiological function in diverse organisms.

Arabidopsis gtg1 gtg2 mutants show defects in root and hypocotyl growth; reduced seed yield and silique length; pollen germination and pollen tube extension, and cellular deformation.
Arabidopsis gtg1 gtg2 phenotypes

Membrane proteins play important physiological roles in all organisms with fundamental functions including transport, signalling, and bioenergetics. This project focusses on a unique membrane protein class that is highly conserved in eukaryotes: the G protein coupled receptor type-G proteins Golgi pH regulator (GTG/GPHR) family. This project builds on our recent breakthroughs using Arabidopsis and C.elegans demonstrating that plant and animal GTGs are critical for growth and fertility. Plant gtg1gtg2 knockout mutants have serious defects in root and shoot growth and cell structure (Fig. 1). Our work indicates that in plants, GTG proteins are required for Golgi function, cell wall synthesis and light-regulated growth, which are all crucial processes in plant growth and development and therefore critical to the global priorities of food security and bioenergy (Jaffe et al. 2012, Plant Cell 24, 3649-3668).

Given the significant sequence similarity between members of the GTG/GPHR family, the ER/Golgi localization of the plant GTG proteins (Fig. 2) and the proposed functioning of the mammalian GPHR as an anion channel, we hypothesise that the GTG/GPHR family has a conserved physiological function as anion channels regulating endomembrane pH.

Controlling the pH of endomembrane compartments is fundamental to the processes of membrane trafficking, secretion and glycosylation, which are key to eukaryotic physiology. It is predicted that anion channels must be present to neutralise the positive charge building up inside the vesicles as a result of V-ATPase activity, thus allowing the pump to continue pumping protons and ensuring appropriate acidification of compartments. This project uses a range of molecular, biochemical and imaging techniques to investigate this family of membrane proteins.

Principle Investigator (PI): Dr. Lorraine E. Williams
Funding: BBRSC
Funding dates: May 2007-April 2010 & May 2014-April 2017

Related research groups

Environmental Biosciences
Share Share this on Facebook Share this on Twitter Share this on Weibo
Privacy Settings