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Single-Molecule Imaging of Nuclear Transport
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Transportin-1: A Nuclear Import Receptor with Moonlighting Functions
Allegra Mboukou1, Vinod Rajendra2, Renata Kleinova2
1Expression Génétique Microbienne, Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université de Paris, Paris, France.
Frontiers in Molecular Biosciences
|March 8, 2021
Summary
Transportin-1 (Trn1), a nuclear import receptor, mediates the transport of specific proteins into the cell nucleus. Recent studies reveal its complex cargo recognition and novel functions beyond nuclear import, including roles in virus uncoating and protein phase separation.
Area of Science:
- Cell Biology
- Molecular Biology
- Structural Biology
Background:
- Transportin-1 (Trn1), also known as karyopherin-β2 (Kapβ2), is a key nuclear import receptor in the karyopherin-β family.
- While Trn1's role in nuclear import is established, its cargo recognition mechanisms and additional cellular functions are still under active investigation.
Purpose of the Study:
- To review the structural and functional aspects of Trn1-mediated nuclear import.
- To explore the emerging 'moonlighting' activities of Trn1 outside its canonical nuclear import function.
Main Methods:
- Literature review of molecular and structural studies on Trn1.
- Analysis of recent reports on Trn1's non-canonical functions.
Main Results:
- Trn1 recognizes specific nuclear localization signals (NLSs), particularly PY-NLSs, though understanding of non-PY-NLS recognition is evolving.
- Trn1 exhibits diverse functions beyond nuclear import, including involvement in virus uncoating, ciliary transport, and modulation of protein phase separation.
Conclusions:
- Trn1 possesses a complex cargo recognition system with ongoing research into non-PY-NLS substrates.
- Trn1's 'moonlighting' activities highlight its multifaceted roles in cellular processes, expanding beyond its established nuclear import function.
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