Imperial College London: Light shed on cell-entry control mechanisms

Research lead

The means by which transporter proteins provide a border control service, allowing cells to take up some chemicals and substances from their surroundings, whilst keeping others out, has been revealed in unprecedented molecular detail by scientists at Imperial College London, working with teams in the UK, Japan, Denmark and Thailand.

So Iwata from the Division of Molecular Biosciences in the Department of Life Sciences, said the research is important because transporter proteins play an important role letting different substances, including salts, sugars and amino acids, into cells and are the targets for a large number of drugs. “Understanding the details of how this transport mechanism works may help researchers to design new, more effective, drugs in the future,” he said.

The scientists visualised a protein called Microbacterium hydantoin permease, or Mhp1, that is present in the cell membrane of bacteria, allowing access through the cell wall to a hydantoin molecule. This is the first time scientists have been able to show how a transporter protein opens and closes to allow molecules across the membrane and into the cell, by accurate analysis of its molecular structure in different states. 

Iwata and his colleagues analysed the structure of Mhp1 using the facilities at the Membrane Protein Laboratory (MPL), which is an Imperial College outstation at the Diamond Light Source synchrotron in Oxfordshire, UK.

 “Our research has revealed the detailed molecular function of an important membrane protein. We now know how the protein facilitates the movement of hydantoin across the cell membrane without letting any other substances through at the same time,” said Iwata. “This mechanism is likely to be shared by many cell membrane proteins, including those in the human body.”