Ion transporter

In biology, an ion transporter is a transmembrane protein that moves ions (or other small molecules) across a biological membrane to accomplish many different biological functions, including cellular communication, maintaining homeostasis, energy production, etc.^[1] There are different types of transporters including pumps, uniporters, antiporters, and symporters. Active transporters or ion pumps are transporters that convert energy from various sources—including adenosine triphosphate (ATP), sunlight, and other redox reactions—to potential energy by pumping an ion up its concentration gradient.^[2] This potential energy could then be used by secondary transporters, including ion carriers and ion channels, to drive vital cellular processes, such as ATP synthesis.^[3]

This page is focused mainly on ion transporters acting as pumps, but transporters can also function to move molecules through facilitated diffusion. Facilitated diffusion does not require ATP and allows molecules, that are unable to quickly diffuse across the membrane (passive diffusion), to diffuse down their concentration gradient through these protein transporters.^[4]

Ion transporters are essential for proper cell function and thus they are highly regulated by the cell and studied by researchers using a variety of methods. Some examples of cell regulations and research methods will be given.