Week In Science

"Intra-cellular trafficking" discoveries of University of Illinois at Chicago researchers were revealed in a UIC News Release entitled 'Molecular Mechanism Provides Intra-Cellular Traffic Signal.' The cellular traffic management process is well coordinated so as to allow for "maximum flow through cellular compartments." Yeast cells were used in the study however it is believed that the discovered mechanisms have counterparts in other mammalian cells including humans.

Together with cellular membranes intra-cellular mechanisms affect substances flowing both in and out of cells. Malfunctions of intra-cellular pathways can cause disease and cancer.

With respect to the specifics of the molecular mechanisms the article had this to say:

"A special set of proteins is responsible for the coordination. Molecular switches that go by the letters Ypt allow membrane-enclosed vesicles to pass in and out of cellular compartments. Activator proteins flip the switches on. One activator protein, called TRAPP, coordinates two Ypt switches for quick entrance and subsequent exit from a central cellular compartment known as the Golgi apparatus.

Specific subunits of TRAPP previously identified by the UIC researchers were found to be the key to coordinated switching and traffic flow through the Golgi. They have now shown that components of TRAPP act in sequence to direct the flow. One form of TRAPP turns on the first Ypt for entry into the Golgi, while at the other end of the Golgi, two subunits join TRAPP to activate the Ypt required for exit from the Golgi, Segev said."