title: Model system to study classical nuclear export signals.
abstract: Signal-mediated protein transport through the nuclear pore complex is of considerable interest in the field of molecular pharmaceutics. Nuclear localization signals can be used to target genes/antisense delivery systems to the nucleus. Studying nuclear export is useful in enhancing the expression and the efficiency of action of these therapeutic agents. The mechanism of nuclear import has been well studied and most of the proteins participating in this mechanism have been identified. The subject of nuclear export is still in the initial stages, and there is a considerable amount of uncertainty in this area. Two main export receptors identified so far are Exportin 1 (Crm1) and Calreticulin. Crm1 recognizes certain leucine-rich amino acid sequences in the proteins it exports called classical nuclear export signals. This paper describes a model system to study, identify, and establish these classical nuclear export signals using green fluorescent protein (GFP). Two putative export signals in the human progesterone receptor (PR) and the strongest nuclear export signal known (from mitogen activated protein kinase kinase [MAPKK]) were studied using this model system.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, 421 Wakara Way #318, Salt Lake City, UT 84108, USA.
authors.forename: Charu
authors.initials: C
authors.lastname: Kanwal
authors.forename: Henan
authors.initials: H
authors.lastname: Li
authors.forename: Carol S
authors.initials: CS
authors.lastname: Lim
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D037282:Calreticulin / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism*; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D049452:Green Fluorescent Proteins; D006801:Humans; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D015674:Mammary Neoplasms, Animal / Q000235:genetics / Q000473:pathology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals / Q000235:genetics / Q000502:physiology*; D018160:Receptors, Cytoplasmic and Nuclear; D011980:Receptors, Progesterone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D000097606:Exportin 1 Protein
chemical_list: D037282:Calreticulin; D049452:Green Fluorescent Proteins; D028884:Karyopherins; D008164:Luminescent Proteins; D020929:Mitogen-Activated Protein Kinase Kinases; D021382:Protein Sorting Signals; D018160:Receptors, Cytoplasmic and Nuclear; D011980:Receptors, Progesterone; D011993:Recombinant Fusion Proteins; D000097606:Exportin 1 Protein