In an article published in Science, researchers report progress on the determination of the structure of the nuclear pore complex, “an incredibly discriminating gatekeeper for the cell’s nucleus.”
Whatever you are doing, whether it is driving a car, going for a jog, or even at your laziest, eating chips and watching TV on the couch, there is an entire suite of molecular machinery inside each of your cells hard at work. That machinery, far too small to see with the naked eye or even with many microscopes, creates energy for the cell, manufactures its proteins, makes copies of its DNA, and much more.
Among those pieces of machinery, and one of the most complex, is something known as the nuclear pore complex (NPC). The NPC, which is made of more than 1,000 individual proteins, is an incredibly discriminating gatekeeper for the cell’s nucleus, the membrane-bound region inside a cell that holds that cell’s genetic material. Anything going in or out of the nucleus has to pass through the NPC on its way.
The NPC’s role as a gatekeeper of the nucleus means it is vital for the operations of the cell. Within the nucleus, DNA, the cell’s permanent genetic code, is copied into RNA. That RNA is then carried out of the nucleus so it can be used to manufacture the proteins the cell needs. The NPC ensures the nucleus gets the materials it needs for synthesizing RNA, while also protecting the DNA from the harsh environment outside the nucleus and enabling the RNA to leave the nucleus after it has been made.
The implications of this research are potentially huge. Not only is the NPC central to the operations of the cell, it is also involved in many diseases. Mutations in the NPC are responsible for some incurable cancers, for neurodegenerative and autoimmune diseases such as amyotrophic lateral sclerosis (ALS) and acute necrotizing encephalopathy, and for heart conditions including atrial fibrillation and early sudden cardiac death. Additionally, many viruses, including the one responsible for COVID-19, target and shutdown the NPC during the course of their lifecycles.
The assembly of the NPC’s outer face also helped solve a longtime mystery about the nuclear envelope, the double membrane system that surrounds the nucleus. Like the membrane of the cell within which the nucleus resides, the nuclear membrane is not perfectly smooth. Rather, it is studded with molecules called integral membrane proteins (IMPs) that serve in a variety of roles, including acting as receptors and helping to catalyze biochemical reactions.Phys.Org
The nuclear pore complex is said to be composed of more than 1000 proteins, operating to form one of most complex pieces of molecular machinery within the cell. Consider that the probability of forming even one protein is miniscule, given the laws of physics in our universe, let alone 1000 proteins operating in concert. And yet some would claim that there is no evidence for intelligent design!