As I mentioned in an earlier post, some scientific projects have a certain amount of notoriety cued up and waiting for whomever gets to finish line X first. A good example is prion proteins, the cause of a particularly baffling set of illensses that include mad cow and Creutzfelt-Jakob diseases. Unlike any other disease that we know about, prion diseases don’t pass from person to person via a virus or a bacteria or any other sort of living agent but instead constitute a single misfolded protein. The problem is that the single protein can induce other proteins to misfold, which then set off a chain reaction that leaves the brain spongy and riddled with insoluble protein aggregates.
After years of fierce controversy we’ve gained a relatively good idea of how the prion protein (PRP) changes from its innocuous form to the misfolded, disease state. As a result we have a few good pointers for staying healthy. First, don’t eat people. The first known prion disease, kuru, mystified anthropologists who found no infectious reason for the fatal wasting disease afflicting members of a New Guinea tribe of cannibals. As it turns out the acid environment of our stomach is a great place for PRP to slip out of its usual conformation and into the killer state. Similarly, don’t feed cow tissue to cows. The same rule that applies to us applies to them. Finally, you can get it from cows but only if they already have the misfolded protein, so avoid brain tissue of questionable provenance.
The most important thing that we didn’t know, until now, is what exactly PRP does when it isn’t killing people (1).
Harvey Lodish at the Whitehead Institute in Cambridge, Massachusetts, and his co-workers stumbled on one answer when studying mouse stem cells that divide to generate new blood cells. They found that many of these stem cells have prion proteins stuck all over their surfaces.
The team shows that these prions help stem cells from the bone marrow to manufacture more and more new blood cells.
…Stem cells that lacked the prion protein wore out, and were unable to manufacture new cells, long before those that carried working prions. “It’s a first clue to what these proteins might do,” Lodish says, who reports the findings in the Proceedings of the National Academy of Sciences(2).
In a nutshell, we need the prion protein in order to keep our stem cells alive. Some kinds of work can be pretty hard to present to a mixed audience in a way that makes sense and conveys why it’s interesting; these guys have it made. In the global race for stem cell technology score one for America.
Treat this as an open science thread. Yes, that includes manimals.