*********************Alzheimer's molecule is a smart speed bump on the nerve-cell transport highway -- PHYSORG.com
Differential regulation of dynein and kinesin motor proteins by the microtubule associated protein tau. The Penn group found that dynein, which carries loads towards the interior of the nerve cell, maneuvers around tau; whereas, kinesin, which carries loads towards the outside of the nerve cell, detaches when it encounters tau. Credit: Credit: Ram Dixit, PhD, University of Pennsylvania School of Medicine
Researchers at the University of Pennsylvania School of Medicine discovered that proteins carrying chemical cargo in nerve cells react differently when exposed to the tau protein, which plays an important role in Alzheimer’s disease.
Dynein and kinesin proteins transport cellular cargo towards opposite ends of tracks called microtubules. Tau binds to the microtubule surface and acts like a speed bump to regulate protein traffic, the group found. “But it is a smart speed bump because it impedes these different motor proteins to different degrees,” explains first author Ram Dixit, PhD, a postdoctoral fellow in the lab of senior author Erika Holzbaur, PhD, Professor of Physiology.
“Our findings show a mechanism of regulating the transport of nutrients, signaling molecules, and waste proteins along a nerve cell’s axon,” says Dixit. “Neurodegenerative diseases such as Alzheimer’s arise when pieces of this shipping system goes awry.”
Then from this link I found an animation of the motor protein in action. It's from Harvard Medical School and the motor protein “walking” along the microtubules is about 2 minutes in.
http://multimedia.mcb.harvard.edu/anim_innerlife.html
When you think of it, the life-time-span of these inner cellular objects is very similar to Man's life-time-span to our Solar System -- not even a blip on the cosmic consciousness, yet can have profound (and debilitating) results. Or not.
Cheers.
