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Bioengineering/biophysics
seminar at
Professor
Yitzhak Rabin
Transport
of DNA and proteins through nuclear pores Location:
ERB 203,
Date:
Time: Abstract All the transport between the cytoplasm and the nucleoplasm of eukarotic cells
takes place through the nucleopores which are large
protein complexes (NPC) that permeate the nuclear membrane. We present
experimental results on the translocation of DNA through the
NPC of reconstituted nuclei, and discuss the origin of the anomalously slow
rate of translocation and the slowing down of entry with time. We then discuss
the mystery of protein translocation across the NPC – while small
proteins and gold particles go through by passive diffusion, the translocation
of large cargoes proceeds only through the formation of even larger cargo-NLS-importin complexes (CIC), that go
through the pore without ATP/GTP consumption! We propose a model according to
which (a) the NPC is blocked by a protein network (FG Nups)
whose open and closed states are separated by a large free energy barrier and
(b) the CIC acts as a catalyst that can reduce the barrier and pass through.
The results of Brownian dynamics simulations based on this model are presented.
____________________ Prof. Physics Department Phone: 617 353 2969 FAX: 617 353 9393 |