Biomaterial Database

The heterologous expression of H(+)-coupled transporters in Xenopus oocytes. 1994

A J Miller, and S J Smith, and F L Theodoulou

Biochemistry and Physiology Department, Rothamsted Experimental Station, AFRC-IACR, Harpenden, Hertfordshire, UK.

The Xenopus oocyte has become a convenient and robust system for the expression of many different animal transport proteins and it has now been demonstrated that oocytes can also translate, process and target plant membrane proteins. Here we review the background to this expression system and discuss how it can be used to express plant transporters. A H+/hexose cotransporter (STP1) from Arabidopsis thaliana has been successfully expressed in oocytes and further characterization has shown the transporter to have properties similar to the same transporter expressed in yeast. However, the expression of H(+)-coupled transporters may present problems for oocyte intracellular pH regulation, because the influx of protons during their operation may acidify the cell. To investigate this possibility, proton-selective microelectrodes have been used to measure intracellular pH during symport of H+ and hexose in oocytes expressing STP1. These measurements showed that oocyte cytosolic pH is unaltered during H+/glucose cotransport, but is sensitive to changes in external pH.

UI	MeSH Term	Description	Entries
D009865	Oocytes	Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).	Ovocytes,Oocyte,Ovocyte
D010940	Plant Proteins	Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which PLANT PROTEINS, DIETARY is available.	Plant Protein,Protein, Plant,Proteins, Plant
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D005260	Female		Females
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014981	Xenopus	An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.
D015870	Gene Expression	The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.	Expression, Gene,Expressions, Gene,Gene Expressions
D017494	Proton Pumps	Integral membrane proteins that transport protons across a membrane. This transport can be linked to the hydrolysis of ADENOSINE TRIPHOSPHATE. What is referred to as proton pump inhibitors frequently is about POTASSIUM HYDROGEN ATPASE.	H(+) Pump,H+ Pump,Proton Pump,Pump, H+,Pump, Proton,Pumps, Proton