Transportin-1 and Transportin-2: protein nuclear import and beyond.
Nearly 20 years after its identification as a new β-karyopherin mediating the nuclear import of the RNA-binding protein hnRNP A1, Transportin-1 is still commonly overlooked in comparison with its best known cousin, Importin-β. Transportin-1 is nonetheless a considerable player in nucleo-cytoplasmic transport. Over the past few years, significant progress has been made in the characterization of the nuclear localization signals (NLSs) that Transportin-1 recognizes, thereby providing the molecular basis of its diversified repertoire of cargoes. The recent discovery that mutations in the Transportin-dependent NLS of FUS cause mislocalization of this protein and result in amyotrophic lateral sclerosis illustrates the importance of Transportin-dependent import for human health. Besides, new functions of Transportin-1 are emerging in processes other than nuclear import. Here, we summarize what is known about Transportin-1 and the related β-karyopherin Transportin-2.
Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium. Electronic address: ltwyffel@ulb.ac.be.
Laure
L
Twyffels
Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium.
Cyril
C
Gueydan
Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium.
Véronique
V
Kruys
D021581:Active Transport, Cell Nucleus; D002467:Cell Nucleus / Q000378:metabolism*; D002923:Cilia / Q000502:physiology; D015870:Gene Expression; D006801:Humans; D008938:Mitosis / Q000502:physiology; D008954:Models, Biological; D019913:Nuclear Localization Signals / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D028961:beta Karyopherins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D019913:Nuclear Localization Signals; C108121:TNPO1 protein, human; C503621:TNPO2 protein, human; D028961:beta Karyopherins
FUS; Importins; Kap104p; Karyopherin-β2; Karyopherins; NLS; Nuclear import; Nucleo-cytoplasmic transport; Transportin; Transportin-1; Transportin-2; hnRNP A1