Selectivity of transport through the nuclear pore complex: from nuclear import to bio-sensors
Tuesday, July 21, 2009
2:15 pm - 3:15 pm
CNLS Conference Room (TA-3, Bldg 1690)
Selectivity of transport through the nuclear pore complex: from nuclear import to bio-sensors
Anton Zilman, Oppenheimer Fellow
Nuclear Pore Complex (NPC) is a multi-protein cellular machine that gates the transport between the cell nucleus and the cytoplasm. NPC’s are able to selectively transport hundreds of molecules per second in both directions, without a direct input of metabolic energy and without large scale transitions of the cnahhel from an ‘open’ to a ‘closed’ state. The transport selectivity is based not on high-affinity ‘lock-and-key’ interactions of the transported molecules with the channel but rather on a low-affinity transient binding of the transport factors that shuttle cargoes through the NPC.
Despite extensive experimental and theoretical research, selectivity of the NPC is still not fully understood. I will review a model of the NPC selectivity that takes into account only the basic properties of the stochastic kinetics of transport through narrow channels. This minimal model provides insights into how the transient binding of the transport factors and their confinement in the limited space within the NPC combine to provide selective transport, even in the presence of large amounts of competing molecular species that may interact non-specifically with the NPC. Predictions of the theory have lead to the creation of an artificial nano-filter that mimics the selectivity of the NPC and confirms the theoretical predictions. Finally, I will discuss how the minimal model is applicable to the transport through a large class of biological and artificial selective nano-channels.
