Assays

A wide variety of different transporters, pumps and channels have been investigated successfully using IonGate's SURFE²R™ technology, demonstrating the broad applicability and power of this cell-free, membrane-based measurement system.

Various types of membrane preparations such as proteoliposomes, native membranes, or membranes from cultured cells can be used for SURFE²R measurements. Heterologous expression systems suitable for the production of recombinant target proteins range from bacterial expression to mammalian or insect cell cultures. For an overview please refer to the table below.

Electrophysiology is a powerful tool for the investigation of transport processes. As in conventional electrophysiology, the SSM-based approach is suitable for testing proteins from both the cytosolic and extracytosolic sides. Typically, transport proteins and channels are activated via substrate or ligand concentration jumps (PEPT1, PAT, nAChR, P2X2). In addition, chemical gradients of different ions such as sodium, potassium or chloride can be established to monitor activity of ion-coupled transporters (NCX, SGLT, CNT, EAAC1). Also proton-dependent transport mechanisms can be investigated (PEPT, PAT). Specific anion gradients can be applied to generate membrane potential for driving potential-dependent transporters.

At present, there are several applications that make the SURFE²R technology unique positioning the technique clearly ahead of standard electrophysiological approaches used in the study of membrane transport proteins: