Nav: Home

Synthetic nanochannels for iodide transport

June 08, 2017

Exchange of iodide (iodine ions) between bloodstream and cells is crucial for the health of several organs and its malfunctioning is linked to goiter, hypo- and hyperthyroidism, breast cancer, and gastric cancer. Researchers at the Center for Self-Assembly and Complexity, within the Institute for Basic Science (IBS) have devised nanostructures that function as channels for iodide transport in cell membranes. This study, published in the Journal of the American Chemical Society (JACS), may lead to diagnosis and treatment of iodide transport disorders.

A protein known as a sodium/iodide symporter (NIS) mediates the transport of iodide from the bloodstream into thyroid cells as well as other tissues, including mammary glands during lactation, cancerous breast tissues, and lacrimal glands. NIS is a hollow structure spanning the height of the cell membrane through which iodide can move into the cells.

IBS scientists developed synthetic ion channels that selectively allow the passage of negatively-charged ions, especially iodides. With a diameter of 3.64 nm and the right chemical characteristics, these channels called porphyrin boxes 1A (PB-1A), fit into the cellular membrane.

PB-1A has the shape of a 26-faced polyhedron made of triangles and squares, named rhombicuboctahedron by Archimedes. Two types of molecules make up 14 faces of the solid, while the other faces are left empty for the ions to pass through.

PB-1A has the advantage of being chemically stable in aqueous solution and in the cell membrane. IBS scientists found that PB-1A naturally inserts itself into the cell membrane, is functional as an ion channel, and non-toxic to cells.

The team observed that different types of negatively-charged ions can go through PB-1A, but some can do it better than others. For example: iodide transfer about 60 times more efficiently than chloride, the most abundant biological negatively-charged ion, that is twice more selective than previously reported channels. The team observed that different types of negatively-charged ions can go through PB-1A, but some can do it better than others. For example: iodide transfers about 60 times more efficiently than chloride, the most abundant biological negatively-charged ion, which is twice more selective than previously reported channels. This difference in efficiency is related to the water molecules surrounding the ions and the energy required to pull out them out, i.e. it is easier for iodide to remove these water molecules as it goes through the channel, which facilitates its passage.

Designing channels with high selectivity for specific ions is not a trivial task. "We are excited by these findings, because in comparison with studies on chloride channels and channels that transport positively-charged ions, iodide-selective artificial channels have been rarely reported in the last decade. Moreover, channels that mimic the functions of NIS are very interesting, as they have the potential to treat thyroid and non-thyroid malignancies," points out Dr. ROH Joon Ho, one of the corresponding authors of this study.

In the future, IBS researchers aim to develop smart synthetic ion channels gated by light.

Institute for Basic Science

Related Cell Membrane Articles:

Similar lipids cluster in soybean cell membrane model
Researchers have developed a detailed computational model of the soybean plasma membrane that provides new structural insight at the molecular level, which may have applications for studying membrane proteins and may be useful for engineering plants to produce biochemicals, biofuels, drugs and other compounds, and in understanding how plants sense and respond to stressful conditions.
Neutrons provide the first nanoscale look at a living cell membrane
A research team from the Department of Energy's Oak Ridge National Laboratory has performed the first-ever direct nanoscale examination of a living cell membrane.
Membrane lipids hop in and out of rafts in the blink of an eye
New fluorescent lipids demonstrate how specialized regions in the cell membrane function.
Fighting MRSA with new membrane-busting compounds
Public health officials are increasingly concerned over methicillin-resistant Staphylococcus aureus (MRSA).
Biophysicists propose new approach for membrane protein crystallization
Membrane proteins are of great interest to both fundamental research and applied studies (e.g., drug development and optogenetics).
A new way to discover structures of membrane proteins
University of Toronto scientists have discovered a better way to extract proteins from the membranes that encase them, making it easier to study how cells communicate with each other to create human health and disease.
3-D printing could transform future membrane technology
Researchers at the University of Bath suggest developments in 3-D printing techniques could open the door to the advancement of membrane capabilities.
Collapse of mitochondria-associated membrane in ALS
Mitochondria-associated membrane (MAM) is a contacting site of endoplasmic reticulum and mitochondria, and plays a key role in cellular homeostasis.
The molecular mechanism that blocks membrane receptors has been identified
Nearly 70 percent of the drugs currently being developed target membrane receptors.
Membrane fluidity influences sensitivity of ovarian cancer cell lines to auranofin
Increased fluidity in cell membranes could have a major impact on an ovarian cancer cell's sensitivity to treatment using the anti-rheumatic drug auranofin, research led by Plymouth University suggests.

Related Cell Membrane Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...