Mechanism for signal transduction in the induced-raft domains as revealed by single-molecule tracking

作者：Suzuki Kenichi G N^*; Kusumi Akihiro

来源：Trends in Glycoscience and Glycotechnology, 2008, 20(116): 341-351.

DOI：10.4052/tigg.20.341

• single-molecule tracking
• plasma membrane
• membrane skeleton
• signal transduction
• induced raft domain

Raft domains have been proposed to work as a platform where raftophilic signaling molecules assemble and interact for efficient signal transduction. However, this raft hypothesis has been difficult to prove. Our recent single-molecule tracking experiments revealed that cytoplasmic signaling molecules were frequently, but very transiently recruited to the rafts formed on demand by the clusters of raftophilic glycosylphosphatidylinositol (GPI)-anchored receptors (e.g., CD59) that were generated after the engagement of the receptors by the binding of extracellular signaling molecules. All of the cytoplasmic signaling molecules examined thus far, G alpha i2, Lyn, and PLC gamma, exhibited short residency times of similar to 200 ms within the CD59-cluster rafts. This recruitment period of each individual signaling molecule was short, compared with the periods of overall bulk activation of these molecules by a factor of 4,000. Argument has been advanced that the analogue bulk signal, which lasts for over several thousands seconds, is generated by the superposition of the short-lived, digital-like individual signals, which last for a fraction of a second.

• 出版日期2008