Differential nucleocytoplasmic shuttling of beta-arrestins. Characterization of a leucine-rich nuclear export signal in beta-arrestin2.
beta-arrestins (betaarrs) are two highly homologous proteins that uncouple G protein-coupled receptors from their cognate G proteins, serve as adaptor molecules linking G protein-coupled receptors to clathrin-coat components (AP-2 complex and clathrin), and act as scaffolding proteins for ERK1/2 and JNK3 cascades. A striking difference between the two betaarrs (betaarr1 and betaarr2) is that betaarr1 is evenly distributed throughout the cell, whereas betaarr2 shows an apparent cytoplasmic localization at steady state. Here, we investigate the molecular determinants underlying this differential distribution. betaarr2 is constitutively excluded from the nucleus by a leptomycin B-sensitive pathway because of the presence of a classical leucine-rich nuclear export signal in its C terminus (L395/L397) that is absent in betaarr1. In addition, using a nuclear import assay in yeast we showed that betaarr2 is actively imported into the nucleus, suggesting that betaarr2 undergoes constitutive nucleocytoplasmic shuttling. In cells expressing betaarr2, JNK3 is mostly cytosolic. A point mutation of the nuclear export signal (L395A) in betaarr2, which was sufficient to redistribute betaarr2 from the cytosol to the nucleus, also caused the nuclear relocalization of JNK3. These data indicate that the nucleocytoplasmic shuttling of betaarr2 controls the subcellular distribution of JNK3.
Scott
Mark G H
MG
Department of Cell Biology, Institut Cochin, Pavillon Gustave Roussy, 75679 Paris CEDEX 14, France.
Le Rouzic
Erwann
E
Périanin
Axel
A
Pierotti
Vincenzo
V
Enslen
Hervé
H
Benichou
Serge
S
Marullo
Stefano
S
Benmerah
Alexandre
A
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D019390:Arrestins / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D007930:Leucine; D008164:Luminescent Proteins / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection; D000071557:beta-Arrestins
D019390:Arrestins; D008164:Luminescent Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D000071557:beta-Arrestins; D049452:Green Fluorescent Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D007930:Leucine