Molecular basis for dissimilar nuclear trafficking of the actin-bundling protein isoforms T- and L-plastin.
T- and L-plastin are highly similar actin-bundling proteins implicated in the regulation of cell morphology, lamellipodium protrusion, bacterial invasion and tumor progression. We show that T-plastin localizes predominantly to the cytoplasm, whereas L-plastin distributes between nucleus and cytoplasm in HeLa or Cos cells. T-plastin shows nuclear accumulation upon incubation of cells with the CRM1 antagonist leptomycin B (LMB). We identified a Rev-like nuclear export sequence (NES) in T-plastin that is able to export an otherwise nuclear protein in an LMB-dependent manner. Deletion of the NES promotes nuclear accumulation of T-plastin. Mutation of residues L17, F21 or L26 in the T-plastin NES inhibits nuclear efflux. L-plastin harbors a less conserved NES and lacks the F21 T-plastin residue. Insertion of a Phe residue in the L-plastin NES specifically enhances its export activity. These findings explain why both isoforms exhibit specific distribution patterns in eukaryotic cells.
Delanote
Veerle
V
Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, A. Baertsoenkaai 3, B-9000, Ghent, Belgium.
Van Impe
Katrien
K
De Corte
Veerle
V
Bruyneel
Erik
E
Vetter
Guillaume
G
Boucherie
Ciska
C
Mareel
Marc
M
Vandekerckhove
Joël
J
Friederich
Evelyne
E
Gettemans
Jan
J
D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002522:Chlorocebus aethiops; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D015694:Gene Products, rev / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007930:Leucine / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010641:Phenotype; D010649:Phenylalanine / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D021382:Protein Sorting Signals / Q000187:drug effects; D016415:Sequence Alignment
D005231:Fatty Acids, Unsaturated; D015694:Gene Products, rev; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D020033:Protein Isoforms; D021382:Protein Sorting Signals; C052523:actin filament bundling proteins; C026742:plastin; D010649:Phenylalanine; D007930:Leucine; C038753:leptomycin B