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IMB Seminar - Sandra Encalada

IMB Seminar

Date: Tuesday, May 14, 2013

Location 110 Willamette Hall

Time: 4:00 - 5:00 P.M.

Guest Speaker: Sandra Encalada, The Scripps Research Institute, Department of Molecular and Experimental Medicine, Dorris Neuroscience Center

Seminar Title: Mechanisms of Fast Axonal Transport of Prion Protein Vesicles and Infectious Prions

Host: Bruce Bowerman


Movement and positioning of vesicles inside axons is accomplished by the regulated active transport of kinesin and
dynein motor proteins, which move along microtubules in anterograde and retrograde directions, respectively. The
normal mammalian prion protein (PrPC) is a GPI-anchored protein that follows the secretory pathway inside vesicles
toward the cell surface by an unknown mechanism. Once at the cell surface, PrPC is thought to interact with a number
of ligands, including infectious scrapie (PrPSc), if present. Thus, trafficking of PrPC to the plasma membrane via an
intact transport system might be a relevant mechanism for initiation of neurodegenerative conditions. Using imaging,
biochemical, and genetic approaches, we show differential transport of the prion protein along axons by Kinesin-1 and
cytoplasmic dynein. We show that anterograde and retrograde motors associate to PrPC vesicles regardless of
directionality or speed of movement, suggesting that the activity of these motors is uncoupled from their association to
these vesicles and that regulatory factors instead of structural changes to motor-vesicle associations dictate the
transport mechanics of these vesicles in axons. Furthermore, we show evidence for the fast axonal transport of
infectious prions, and how prion infection might lead to the poisoning of an intact transport system in axons.

For more information see the URLs below:

Tue May 14, 2013 4pm – 5pm Pacific Time
110 Willamette Hall (map)