Paxillin Migration
by MikeGenePaxillin is a protein with multiple domains that hangs out at focal adhesions with various other proteins, including integrins. Focal adhesions are essentially points on the cell membrane where the actin cytoskeleton inside the cell is connected up to the extra-cellular matrix in multi-cellular organisms. Thus, the focal adhesions turn out to be useful nodes for signal transduction, where extra-cellular messages can quickly be converted into intra-cellular messages via activity at these adhesions. Paxillin functions as a multi-purpose adaptor protein that is involved in conveying signals and altering the cell's cytoskeleton.
Recently, researchers at UC San Diego published videos of paxillin migrating from the cell periphery toward the nucleus along the cytoskeletal tracks. The interesting and educational video can be downloaded and viewed here.
One more thing. Paxillin, which is clearly very useful in metazoan life, is also found in unicellular organisms. In fact, according to one study of amoba, the paxillin-related signaling pathway is "similar to the one used in mammalian cells." (Flores-Robles D, Rosales C, Rosales-Encina JL, Talamas-Rohana P. 2003. Entamoeba histolytica: a beta 1 integrin-like fibronectin receptor assembles a signaling complex similar to those of mammalian cells. Exp Parasitol. 103:8-15.
June 4th, 2007 at 12:27 am
I'm going to bed before looking at the video but earlier in the evening I was thinking about the discovery that microRNA was found in green algae. That sounds like something Mike Gene could weave into a future post.
Comment by Bradford — June 4, 2007 @ 12:27 am
June 4th, 2007 at 10:23 am
How is this different from what unguided evolutionary processes would do? Paxillin is found in both unicellular and multicellular organisms doing a similar task. Isn't this something that would fall under the purview of NDE?
Comment by Doug — June 4, 2007 @ 10:23 am
June 5th, 2007 at 10:26 am
Hi Doug,
I don't worry too much whether or not something can "fall under the purview of NDE" as that does not mean NDE indeed accounts for such phenomena. If teleologists restrict themselves to things that cannot possibly be explained by NDE, they are going to be left with very few puzzle pieces.
What I find interesting is that paxillin is part of a sophisticated communication system needed for mammalian life. Yet there are examples of it among unicellular life forms. In fact, what is even more interesting here is that it is used in these parasitic, quasi-multicellular ways. But I have too run.
Comment by MikeGene — June 5, 2007 @ 10:26 am