Directing proteins to nucleus by fusion to nuclear localization signal tags

Abstract

Publisher Summary In all eukaryotic cells, the nucleus is separated from the cytoplasm by the nuclear envelope. Molecules that travel from one compartment to the other use the channels created by large proteinaceous structures termed nuclear pore complexes (NPCs). Proteins enter the nucleus from the cytoplasm through a 25-nm active channel by a facilitated process that often requires the presence of a nuclear localization signal (NLS) on the transported protein as well as soluble transport factors. The necessary transport factors include “receptors” that recognizes the NLS and a small GTPase termed Ran that mediates the association of the receptor with its cargo. Several classes of NLSs require the action of different NLS receptors. The chapter describes the various NLSs, and discusses how they are used by the cell to mediate nuclear protein import. In addition, it presents details on how to use some of these NLSs to target proteins to the nucleus in both mammalian and yeast cells.