Sarma, P. A.

Abstract The nuclear pore complex (NPC) is an excellent example of a bio-molecular motor, since it operates primarily via energy dependent processes, and performs some of the most vital functions required for the survival of a cell. In the presence of appropriate chemical stimuli, the NPC apparently opens or closes, like a gating mechanism, and permits the flow of material in to and out of the nucleus. An NPC, with typical dimensions of 100–200 nm, is a megadalton (MDa) heteromultimeric protein complex, which spans the nuclear envelope and is postulated to possess a transporter-containing central cylindrical body embedded between cytoplasmic and nucleoplasmic rings as shown in Fig.1. A cell has many, presumably identical, NPCs, each of which participates in the import and export of nuclear material from within the nucleus [1–2]. Exactly how this transport occurs through the NPC is an open question, and a very important one, with profound implications for nanoscale devices for fluidic transport, genetic engineering and targeted drug delivery.