(Credit: Image courtesy of Rockefeller University)
From ScienceDaily (Jan. 30, 2008) A cell’s membrane-bound nucleus uses hundreds to thousands of nuclear pores as its gatekeepers, selective membrane channels that are responsible for regulating the material that goes to and from a cell’s DNA. Rockefeller scientists have nailed down the first complete molecular picture of this huge, 450-protein pore and their findings provide a glimpse into how the nucleus itself first evolved.
The group gathered and analyzed massive amounts of data to come up with a rough draft of the structure of the nuclear pore.
The scientists’ results have given them a peek into the early evolution of eukaryotic cells. Compartmentalization was made possible by membranes and coating complexes, which act “like little hands” to grab, shape and stabilize membranes.
“We think that once the cells gained this coating complex, they ran with it and started to duplicate it and specialize it,”
“Evolution is a process of duplication and divergence,” Rockefeller professor Michael Rout says. He and his colleagues saw clear evidence of this. For every protein, there was another one that looked quite similar. “These are evidence of duplication events, showing that the evolution of the complicated nuclear pore was a more straightforward affair than previously thought. It’s made of many different variations of a theme of just one unit.”
“The nuclear pore is the communication device that the nucleus uses to communicate with the rest of the cell. And if you don’t understand how that works, you don’t understand a key part of how the cell works. You have to see the cell as a machine and understand all of its parts.”
refs Nature 450(7170): 683–694 (November 29, 2007): Nature 450(7170): 695–701 (November 29, 2007) Watch the movie here.