Using fast digital imaging, scientists from the Max Planck Institute of Colloids and Interfaces in Potsdam, Germany, together with researchers from Collge de France, have succeeded in developing two different protocols by which one can initiate the fusion process in a controlled manner and observe the subsequent fusion dynamics with a temporal resolution in the microsecond regime. For both protocols, the opening of the fusion necks was found to be very fast, with an average expansion velocity of centimetres per second. This velocity indicates that the initial formation of a single fusion neck can be completed in a few hundred nanoseconds. (Proceedings of the National Academy of Sciences of the USA 103, 15841-15846, October 24, 2006).
The process of membrane fusion is essential for the structure and dynamics of all cells in our bodies. Fusion is indispensable for intracellular vesicle traffic, which sustains the compartmental organisation of cells. Likewise, membrane fusion is the basic molecular process that controls the communication between cells via the secretion of hormones, neurotransmitters, and growth factors. Furthermore, fusion processes are also crucial for the interactions between our cells and various pathogens such as viruses and bacteria. However, in spite of the ubiquity of membrane fusion, many aspects of this process have remained rather controversial. This situation reflects the absence of well-defined protocols by which one can induce fusion in a controlled manner and subsequently study its dynamics with high temporal resolution.
In order to clarify the dynamics of the fusion process in more detail, scientists from the Max Planck Institute of Colloids and Interfaces developed two different protocols for the fusion of unilamellar vesicles, which had a diameter of tens of micrometers but consist of only a single lipid membrane with a thickness of about four nanometers. Even though such a membrane is much thinner than the opti
Contact: Dr. Rumiana Dimova