Tracking of Quantum Dot-labeled CFTR Shows Near Immobilization by C-Terminal PDZ Interactions

• DOI: 10.1091/mbc.e06-08-0670
• Publication Date: 2006-09-21T00:52:43Z
• Authors: Peter M. Haggie; Jung Kyung Kim; Gergely L. Lukacs; A. S. Verkman
• Keywords: PDZ domain; Villin

Mutations in cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-regulated chloride channel, cause fibrosis. To investigate interactions of CFTR living cells, we measured the diffusion quantum dot-labeled molecules by single particle tracking. In multiple cell lines, including airway epithelia, diffused little plasma membrane, generally not moving beyond 100-200 nm. However, became mobile over micrometer distances after 1) truncations carboxy terminus, which contains C-terminal PDZ (PSD95/Dlg/ZO-1) binding motif; 2) blocking green fluorescent protein fusion; 3) disrupting association with actin expression mutant EBP50/NHERF1 lacking its ezrin domain; or 4) skeletal disruption latrunculin. also when cytoskeletal adaptor capacity was saturated overexpressing C terminus. Our data demonstrate remarkable and previously unrecognized immobilization membrane provide direct evidence that coupling to skeleton via EBP50/ezrin is responsible for immobility.