6.10.2008

Cell-ular Communication..



Last year in San Diego scientists Shu Chien and Ying-Li Hu captured on video the intracellular version of a postal delivery service. Reported in the journal Biochemical and Biophysical Research Communications (BBRC), bioengineering researchers at UC San Diego published videos of a key message-carrying protein called paxillin moving abruptly from hubs of communication and transportation activity on the cell surface toward the nucleus. Paxillin, shown in the video above and the image below are highlighted with labeled with a red fluorescence marker to make it stand out in live cells.
Even without video evidence, scientists have confirmed over the past 10 years that higher organisms use paxillin as a transmitter of locomotion and gene-expression signals from several classes of growth-factor receptors to the nucleus. The agent of communication, the cellular cell phone.

Paxillin's malfunctions have been linked to a variety of cancers, tumor metastasis, and other disease processes. Tumor-causing versions of signaling molecules may attach to paxillin and disturb the normal adhesion and growth factor signaling steps required for controlled proliferation and cell growth. Human papilloma virus, which can lead to cervical cancer, produces a protein that binds to paxillin. That interaction may contribute to the carcinogenic potential of the sexually transmitted virus. *note, potential for a building out of AIDS
This filming of paxillin was via cells from the inner membranous lining of a cow aorta. They added genetically engineered proteins tagged with red and green fluorescence markers to the bovine aortic endothelial cells, grew them in tissue culture, and filmed them while they passed fluid across the cells’ surface in a simulation of flowing blood.

Paxillin is found primarily at focal adhesions, busy intersections of activity scattered around the cell’s cytoplasmic membrane. Focal adhesions are regions highly rich with receptors for growth factors (!!!) and they are also structural attachment points that link the extracellular world to the protein filaments and tubes that comprise a cell’s internal cytoskeleton.

Paxillin is the way to tap into the sensory action of the cellular. Now the challange is to try to translate their means of communication. What is the code that is paxillin is the messenger for? Hello Pattern Recognition!

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