Scientists Understand the Logistics of Protein Movement in a Cell
Scientists at Department of Organic Chemistry of University of Geneva (UNIGE) has tracked possibly for the first time the movement of a specific motor protein with a cell. And in the process they have unveiled the distribution network of vital elements necessary for its survival.
The road network in a cell is made of microtubules that are small, rigid tubes that can grow or shrink and allow molecules to move around a cell.
For the purpose of the study, microtubules were recreated and kinesins or motor proteins that move on microtubles and transport cargo were isolated from bacteria. Then scientists prepared 20 different mixtures containing molecule QPD, which is systematically present in the crystals and observed which solution worked.
Following various experiments, the team led by Nicolas Winssinger, professor at the Department of Organic Chemistry of the Faculty of Science at UNIGE. discovered that the formation of these crystals was caused by one of the 45 types of kinesin present in the cell. “With each small step that this kinesin protein takes on the microtubule, it uses energy that leaves a trace identified by the QPD molecule,” continues the Geneva-based researcher. It is from this recognition that the crystals are formed. In this way, the crystals are chemically left behind by the passage of the kinesin, which can be tracked by scientists like a small thumb.
“Until now, it has not been possible to track a particular protein. With current techniques, we couldn’t separate the individual kinesins, so we couldn’t see which path they took precisely,” according to Charlotte Aumeier, Asst Professor of Department of Biochemistry. “Thanks to the development of our new chemical fluorescent dye, we can observe in detail how a protein behaves, which route it takes, its direction or even its preferred path.” For the first time, scientists can visualise the walking path of motor proteins and study the fundamental question of the transport activity and distribution of cargoes in cells.
Photo caption: A precipitating dye generates fluorescent, aster-like crystals (green) in live cells recording the motion of the motor protein kinesin-1 along microtubules. The crystals are centred in the Golgi apparatus (magenta) and extends towards the periphery of the cells, consistently with the transport activity of kinesin-