Protein export from the nucleus

The evolution of the nucleus imposed on eukaryotic cells the necessity to s trictly control exchange of molecules between the nucleus and the remainder of the cell, not only to protect and correctly transmit genetic informatio n, but also to coordinate nuclear and cytoplasmic functions. Studies over t he past 10 years have provided major insights into the molecular mechanisms responsible for transport of molecules between the nucleus and the cytopla sm. In addition, regulation of the nucleocytoplasmic distribution of divers e cellular factors has emerged as one of the most efficient mechanism to ad apt gene expression to the cell environment, for example by controlling the access of transcriptional regulators to their target genes. In this review , we focus on the molecular basis of protein nuclear export that relies on interactions between targeting sequences present on the cargoes, specific e xport receptors or exportins and nuclear pore proteins, with special emphas is on the role of the Ran GTPase and associated proteins in this process.