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Ultrafast diffusion of a fluorescent cholesterol analog in compartmentalized plasma membranes.

ABSTRACT: Cholesterol distribution and dynamics in the plasma membrane (PM) are poorly understood. The recent development of Bodipy488-conjugated cholesterol molecule (Bdp-Chol) allowed us to study cholesterol behavior in the PM, using single fluorescent-molecule imaging. Surprisingly, in the intact PM, Bdp-Chol diffused at the fastest rate ever found for any molecules in the PM, with a median diffusion coefficient (D) of 3.4 µm²/second, which was ?10 times greater than that of non-raft phospholipid molecules (0.33?µm²/second), despite Bdp-Chol's probable association with raft domains. Furthermore, Bdp-Chol exhibited no sign of entrapment in time scales longer than 0.5?milliseconds. In the blebbed PM, where actin filaments were largely depleted, Bdp-Chol and Cy3-conjugated dioleoylphosphatidylethanolamine (Cy3-DOPE) diffused at comparable Ds (medians?=?5.8 and 6.2 µm²/second, respectively), indicating that the actin-based membrane skeleton reduces the D of Bdp-Chol only by a factor of ?2 from that in the blebbed PM, whereas it reduces the D of Cy3-DOPE by a factor of ?20. These results are consistent with the previously proposed model, in which the PM is compartmentalized by the actin-based membrane-skeleton fence and its associated transmembrane picket proteins for the macroscopic diffusion of all of the membrane molecules, and suggest that the probability of Bdp-Chol passing through the compartment boundaries, once it enters the boundary, is ?10× greater than that of Cy3-DOPE. Since the compartment sizes are greater than those of the putative raft domains, we conclude that raft domains coexist with membrane-skeleton-induced compartments and are contained within them.

SUBMITTER: Hiramoto-Yamaki N

PROVIDER: S-EPMC4265843 | biostudies-other | 2014 Jun

REPOSITORIES: biostudies-other

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Ultrafast diffusion of a fluorescent cholesterol analog in compartmentalized plasma membranes.

Hiramoto-Yamaki Nao N Tanaka Kenji A K KA Suzuki Kenichi G N KG Hirosawa Koichiro M KM Miyahara Manami S H MS Kalay Ziya Z Tanaka Koichiro K Kasai Rinshi S RS Kusumi Akihiro A Fujiwara Takahiro K TK

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Cholesterol distribution and dynamics in the plasma membrane (PM) are poorly understood. The recent development of Bodipy488-conjugated cholesterol molecule (Bdp-Chol) allowed us to study cholesterol behavior in the PM, using single fluorescent-molecule imaging. Surprisingly, in the intact PM, Bdp-Chol diffused at the fastest rate ever found for any molecules in the PM, with a median diffusion coefficient (D) of 3.4 µm²/second, which was ∼10 times greater than that of non-raft phospholipid molec ...[more]

PMID: 24506328

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Dataset Information

Ultrafast diffusion of a fluorescent cholesterol analog in compartmentalized plasma membranes.

Publications

Ultrafast diffusion of a fluorescent cholesterol analog in compartmentalized plasma membranes.

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