How does a cell move? Pull the plug on the electrical charge on the inner side of its membrane

Scientists at Johns Hopkins Medicine say that a key to cellular movement is to regulate the electrical charge on the interior side of the cell membrane, potentially paving the way for understanding cancer, immune cell and other types of cell motion.

Their experiments in immune cells and amoeba show that an abundance of negative charges lining the interior surface of the membrane can activate pathways of lipids, enzymes and other proteins responsible for nudging a cell in a certain direction.

The findings, described in the October issue of Nature Cell Biology, advance biologists’ understanding of cell movement and potentially can help explain biological processes associated with movement, such as how cancer cells move and spread beyond the original site of a tumor and how immune cells migrate to areas of infection or wound healing.

“Our cells are moving within our body more than we imagine,” says Peter Devreotes, Ph.D., the Isaac Morris and Lucille Elizabeth Hay Professor and Distinguished Service Professor in the Department of Cell Biology at the Johns Hopkins University School of Medicine. “Cells move to perform many functions, including when they engulf nutrients or when they divide.”

Many of the molecules involved in cell movement become activated in the leading edge of the cell, or where it forms a kind of foot, or protrusion, that orients the cell in a particular direction.

Tatsat Banerjee, a graduate student in Cell Biology and Chemical and Biomolecular Engineering Departments at Johns Hopkins and the lead author of the study, began to notice that negatively charged lipid molecules that line the inner layer of cell membranes were not uniform, as scientists previously thought. He noticed that these set of molecules consistently leave the regions where a cell makes a protrusion. Banerjee had a hunch that a general biophysical property, such as electrical charge, rather than a specific molecule, could be stimulating and organizing the activities of enzymes and other proteins related to cell movement.

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