Mary Shannon Moore
Transport In and Out of the Cell Nucleus
The focus of my laboratory is the elucidation of the molecular mechanisms responsible for the bidirectional movement of macromolecules between the nucleus and the cytoplasm. A variety of substrates are actively (and specifically) transported between these two compartments. Nuclear proteins containing nuclear localization sequences are actively imported as are several of the UsnRNPs. Exported substrates include mRNA, tRNA, and ribosomal subunits as well as a group of proteins that constitutively shuttle into and out of the nucleus. Nucleocytoplasmic exchange is restricted to nuclear pore complexes which are large and complex structures that bridge the double membrane of the nuclear envelope to form aqueous channels linking the cytoplasm and the nucleoplasm. Our work centers on characterizing the targeting signals of the various transport substrates, identifying the cellular machinery that is responsible for signal recognition and movement of the substrate, and in vitro reconstitution of the transport reactions.