The Small GTPase Ran

The Ras-related nuclear protein Ran is a member of the so-called Ras-superfamily of small GTP-binding proteins and hydrolyzing proteins. A variety of edited anthologies related to the Ras-superfamily have appeared over the last decade of the 20th century, but Ran has been under-represented in all of them. This under-representation is not due to the fact that Ran is unimportant or non-abundant. It is almost certainly because Ran was discovered and its functions elucidated only recently, and that some of these functions may not follow the typical Ras-superfamily paradigm. Even workers in the field have difficulty keeping up with the Ran literature, and most outsiders rarely try even though they may be aware that major breakthroughs regarding the mechanisms of nuclear-cytosolic transport, mitosis and the maintenance of nuclear structure have depended upon an understanding of Ran function. This text is meant to provide specialists with a concise summary of some of the research in this area, along with background describing its initial identification and early characterization.