An update on the reverberations of a paradigm-shifting paper in cell biology that began in the MBL Physiology course.
By Alla Katsnelson
The fluid inside a living cell bustles with activity. Proteins, RNA, lipids and other molecules wiggle, zip, glide and drift through this broth — catalyzing reactions, activating receptors, relaying messages, marking viruses and other foreign molecules for destruction and performing a gazillion other tiny but crucial tasks. It all adds up to keep cells — and the life forms they’re a part of — running smoothly.
Biologists have studied these cellular processes for decades. They know an immense amount about the membrane-enclosed organelles inside cells — mitochondria, endoplasmic reticulum, Golgi bodies and more. And they have dissected, often down to atomic-level detail, some of the molecular machinery that drives biological events.
But at the crucial in-between scale, a big question mark remains: How do the right proteins organize themselves in a sea of fluid swarming with millions of molecules? Do they bump into each other by chance, or does the cell actively organize its fluid space to bring the correct partners together?
The latter appears to be true, according to recent research at the intersection of physics and biology. Over the last decade, cell biologists have come to appreciate what many believe to be a whole new way that cells shape their internal landscape. … Read more …
Above: The cytoplasm of a cell is a crowded place. This illustration shows three different components of the cell’s internal skeleton (the blue, rope-like structures), many of the protein-building factories called ribosomes (purple) and numerous other proteins, all crowded together. Credit: David S. Goodsell