Ultrafast Diffusion of a Fluorescent Cholesterol Analog in Compartmentalized Plasma Membranes
Nao Hiramoto-Yamaki, Kenji A. K. Tanaka, Kenichi G. N. Suzuki, Koichiro M. Hirosawa, Manami S. H. Miyahara, Ziya Kalay, Koichiro Tanaka, Rinshi S. Kasai, Akihiro Kusumi and Takahiro K. Fujiwara
Article first published online: 11 MAR 2014 | DOI: 10.1111/tra.12163
A fluorescent cholesterol analogue, Bodipy488-conjugated cholesterol molecule (Bdp-Chol), exhibited diffusion at the fastest rate ever found for any membrane molecules in the plasma membrane, with a median diffusion coefficient of 3.4 µm2/second, ∼10× greater than that of phospholipids, despite Bdp-Chol's probable association with raft domains. Bdp-Chol and phospholipids diffused at comparable rates in the absence of actin membrane-skeleton, indicating that Bdp-Chol hops across the actin-fence-pickets' compartment boundaries ∼10× faster than phospholipids. Raft domains coexist with membrane-skeleton-induced compartments and are contained within them.