Aquaporin-4 (AQP4) associations and array dynamics probed by photobleaching and single-molecule analysis of green fluorescent protein-AQP4 chimeras.

ABSTRACT: The plasma membrane assembly of aquaporin-4 (AQP4) water channels into orthogonal arrays of particles (OAPs) involves interactions of AQP4 N-terminal domains. To study in live cells the site of OAP assembly, the size and dynamics of plasma membrane OAPs, and the heterotetrameric associations of AQP4, we constructed green fluorescent protein (GFP)-labeled AQP4 "long" (M1) and "short" (M23) isoforms in which GFP was inserted at the cytoplasm-facing N or C terminus or between Val-141 and Val-142 in the second extracellular loop of AQP4. The C-terminal and extracellular loop GFP insertions did not interfere with the rapid unrestricted membrane diffusion of GFP-labeled M1 or the restricted diffusion and OAP assembly of GFP-labeled M23. Photobleaching of brefeldin A-treated cells showed comparab

SUBMITTER: Tajima M 

PROVIDER: S-EPMC2832968 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature