Toward understanding the dynamics of membrane-raft-based molecular interactions

The cell membrane is a 2-dimensional non-ideal liquid containing dynamic structures on various time-space scales, and the raft domain is one of them. Existing literature supports the concept that raft dynamics may be important for its formation and function: the raft function may be supported by stimulation-induced raft association/coalescence and recruitment of various raftophilic molecules to coalesced rafts, and, importantly, they both may happen transiently. Thus, one must always consider the limited association time of a raft or a raftophilic molecule with another raft, even when one interprets the results of static experiments, such as immunofluorescence and pull-down assays. Critical considerations on the chemical fixation mechanism and immunocolocalization data suggest that the temporary nature of raft-based molecular interactions may explain why colocalization results are sensitive to subtle variations in experimental conditions employed in different laboratories. (c) 2005 Elsevier B.V. All rights reserved.