Scripps scientists solve protein structure revealing secrets of cell membranes

A team of scientists at The Scripps Research Institute and the National Institutes of Health (NIH) has discovered the structure of a protein that pinches off tiny pouches from cells' outer membranes. Cells use these pouches, or vesicles, to carry nutrients and other essential substances, but many medicines also hitch a ride inside them.

The structure of the protein, called dynamin, is helping to answer many longstanding questions about how vesicles form, advancing knowledge of a process critical to cell survival. The findings may also have implications for designing better ways for delivering drugs.

The research was published on 28 April 2010, in an advance, online issue of the prestigious journal Nature.

The Puzzle of Pinching Off Membranes

The cell membrane typically acts as a barrier around the cell, keeping out harmful materials. But cells also need some substances to get inside.

To get past the membrane, nutrients or hormones in the bloodstream, for example, bind to specific receptors on cells' membranes. The membrane then forms a pit around these bound molecules, which is squeezed into a pouch, or vesicle that detaches from the rest of the cell membrane and carries its essential cargo into the cell. Nerve cells use this same vesicle-making mechanism, called endocytosis, to maintain signaling from one cell to another.

"Endocytosis is how cells communicate," says Sandra Schmid, chair of the Scripps Department of Cell Biology and senior author of the Nature article along with Fred Dyda at NIH. "It's critical for many biological functions from controlling blood pressure to getting rid of glucose."