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Proceedings Paper

Quantum dot single molecule tracking reveals a wide range of diffusive motions of membrane transport proteins
Author(s): Jonathan M. Crane; Peter M. Haggie; A. S. Verkman
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Paper Abstract

Single particle tracking (SPT) provides information about the microscopic motions of individual particles in live cells. We applied SPT to study the diffusion of membrane transport proteins in cell plasma membranes in which individual proteins are labeled with quantum dots at engineered extracellular epitopes. Software was created to deduce particle diffusive modes from quantum dot trajectories. SPT of aquaporin (AQP) water channels and cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels revealed several types of diffusion. AQP1 was freely mobile in cell membranes, showing rapid, Brownian-type diffusion. The full-length (M1) isoform of AQP4 also diffused rapidly, though the diffusion of a shorter (M23) isoform of AQP4 was highly restricted due to its supermolecular assembly in raft-like orthogonal arrays. CFTR mobility was also highly restricted, in a spring-like potential, due to its tethering to the actin cytoskeleton through PDZ-domain C-terminus interactions. The biological significance of regulated diffusion of membrane transport proteins is a subject of active investigation.

Paper Details

Date Published: 3 March 2009
PDF: 10 pages
Proc. SPIE 7189, Colloidal Quantum Dots for Biomedical Applications IV, 71890Y (3 March 2009); doi: 10.1117/12.816900
Show Author Affiliations
Jonathan M. Crane, Univ. of California, San Francisco (United States)
Peter M. Haggie, Univ. of California, San Francisco (United States)
A. S. Verkman, Univ. of California, San Francisco (United States)


Published in SPIE Proceedings Vol. 7189:
Colloidal Quantum Dots for Biomedical Applications IV
Marek Osinski; Thomas M. Jovin; Kenji Yamamoto, Editor(s)

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