(June 26, 2015) The
transportation of certain molecules into and out of the cell nucleus takes
place via nuclear pores. For some time, detailed research has been conducted
into how these pores embedded in the nuclear envelope are structured. Now, for
the first time, biochemists from the University of Zurich have succeeded in
elucidating the structure of the transportation channel inside the nuclear
pores in high resolution using high-performance electron microscopes.
An active exchange takes place between the cell nucleus and
the cytoplasm: Molecules are transported into the nucleus or from the nucleus
into the cytoplasm. In a human cell, more than a million molecules are
transported into the cell nucleus every minute. In the process, special pores
embedded in the nucleus membrane act as transport gates. These nuclear pores
are among the largest and most complex structures in the cell and comprise more
than 200 individual proteins, which are arranged in a ring-like architecture.
They contain a transportation channel, through which small molecules can pass
unobstructed, while large molecules have to meet certain criteria to be
transported. Now, for the first time, an UZH research team headed by Professor
Ohad Medalia has succeeded in displaying the spatial structure of the transport
channel in the nuclear pores in high resolution.