Importin

spinqualitylabelsall models Structure of yeast importinα NLS-binding domain (grey) complex with nucleoplasmin peptide (green) (PDB code 1ee5). Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Function Importins (IPO) mediate the import of cellular proteins into the nucleus by binding to the Nuclear Localization Signal (NLS). IPO has 2 subunits: α and β. IPO-α is an adaptor protein which binds the NLS. IPOs can contain one or two NLS motifs. IPO-α contains several armadillo repeats with two NLS-binding sites and an IPO-β binding (IBB) site. IPO-β contains 19 HEAT (solenoid domain) repeats. Many nuclear proteins contain Phe-Gly sequences which can bind to HEAT repeats and thus be transported. See also Protein Transport Membrane Protein. Disease IPO-α isoform expression is altered in many kinds of cancer. Relevance Specific IPO-α isoforms are critical in nerve regenerative response after injury. Loss of IPO-α expression in aging myocardial cells could make recovery after heart disease in elderly patients more difficult.

3D structures of importin

Updated on 28-December-2017

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• IPO-α
  • Protein Transport Membrane Protein – mIPO NLS-binding domain – mouse
    
  • 1bk5 – yIPO NLS-binding domain - yeast
    
  • 4tnm – IPO armadillo repeat domain – Arabidopsis thaliana
    
• IPO-α complex with NLS peptide
  • 1ejl – mIPO NLS-binding domain + SV40 large T antigen
    
  • 1ejy – mIPO NLS-binding domain + nucleoplasmin
    
  • 2ynr – mIPO NLS-binding domain + B54NLS
    
  • 2yns – rIPO NLS-binding domain + B54NLS - rice
    
  • 1bk6 – yIPO NLS-binding domain + SV40 large T antigen
    
  • 1ee4 – yIPO NLS-binding domain (mutant) + c-Myc
    
  • 1ee5 – yIPO NLS-binding domain (mutant) + nucleoplasmin
    
  • 1un0, 2c1t – yIPO NLS-binding domain (mutant) + Nup2
    
  • 5h2x, 5h2w – yIPO NLS-binding domain + ubiquitin-like specific protease
    
  • 4xzr – yIPO NLS-binding domain + HEH1
    
  • 4pvz – yIPO NLS-binding domain + HEH2
    
  • 4rxh – IPO NLS-binding domain + SV40 large T antigen – Neurospora crassa
    
• IPO-α complex with protein
  • 1wa5 – yIPO NLS-binding domain + GTPase Ran + IPO-α re-exporter
    
• IPO-α 1
  • 3wpt – hIPO NLS-binding domain - human
    
  • 4b8j – rIPO
    
• IPO-α 1 complex with NLS peptide
  • 4mz5, 4mz6 – mIPO NLS-binding domain + dUTPase
    
  • 4oih – mIPO NLS-binding domain + guanine nucleotide exchange factor SRM1
    
  • 5svz – mIPO NLS-binding domain + TAT NLS motif
    
  • 5wum, 5wun, 5x8n – mIPO NLS-binding domain + Epstein Barr antigen
    
  • 5huw – mIPO NLS-binding domain + HSVI large terminase
    
  • 5huy – mIPO NLS-binding domain + HSMV small terminase
    
  • 5hhg, 5fc8 – mIPO NLS-binding domain + dengue 2 NS5
    
  • 5ekg, 5ekf, 5e6q – mIPO NLS-binding domain + XPG2
    
  • 5d5k – mIPO NLS-binding domain + PARP 2
    
  • 5ctt – mIPO NLS-binding domain + SART3/TIP110
    
  • 5b56 – mIPO NLS-binding domain + HIV-1 VPR
    
  • 4zdu – mIPO NLS-binding domain + influenza nucleoprotein
    
  • 4yi0 – mIPO NLS-binding domain + Nup121
    
  • 5klr, 5klt – mIPO NLS-binding domain + NLS
    
  • 5k9s – mIPO NLS-binding domain + HNF-b
    
  • 4b18 – hIPO NLS-binding domain + telomerase reverse transcriptase
    
  • 4wv6 – hIPO NLS-binding domain + TFIID
    
  • 4b8o – rIPO NLS-binding domain + SV40
    
  • 4b8p – rIPO NLS-binding domain + A89
    
  • 4bpl – rIPO NLS-binding domain + nucleoplasmin
    
  • 4bqk – rIPO NLS-binding domain + VirD2
    
• IPO-α 1 complex with protein
  • 2jdq – hIPO NLS-binding domain + polymerase basic protein 2 C terminal
    
  • 3tj3 – hIPO NLS-binding domain + Nup50 N terminal
    
  • 2jdq – hIPO NLS-binding domain + telomerase reverse transcriptase peptide
    
  • 4uaf – mIPO NLS-binding domain + influenza RNA polymerase
    
• IPO-α 2
  • 3tpo – mIPO
    
  • 1iq1 – mIPO NLS-binding + autoinhibitory peptide domains
    
  • 4e4v – hIPO NLS-binding domain (mutant)
    
• IPO-α 2 complex with NLS peptide
  • 1pjm – mIPO NLS-binding domain + retinoblastoma-associated protein
    
  • 1pjn – mIPO NLS-binding domain + histone-binding protein N1/N2
    
  • 1q1s, 1q1t – mIPO NLS-binding domain + SV40 large T antigen
    
  • 1y2a, 3q5u – mIPO NLS-binding domain + phospholipid scramblase
    
  • 2c1m – mIPO NLS-binding domain + Nup50
    
  • 3btr – mIPO NLS-binding domain + androgen receptor
    
  • 3knd – mIPO NLS-binding domain + targeting protein for KXLP2
    
  • 3l3q – mIPO NLS-binding domain + library peptide
    
  • 3oqs – mIPO NLS-binding domain + CLIC4
    
  • 3rz9 – mIPO NLS-binding domain + KU80
    
  • 3rzx – mIPO NLS-binding domain + KU70
    
  • 3tpm – mIPO NLS-binding domain + MAL
    
  • 3ve6 – mIPO NLS-binding domain + Venezuelan equine encephalitis virus
    
  • 3uvu – mIPO NLS-binding domain + flap endonuclease
    
  • 3ukw, 3ukx – mIPO NLS-binding domain + BIMAX
    
  • 3uky, 3ukz, 3ul0 – mIPO NLS-binding domain + nuclear CAP-binding protein
    
  • 3ul1 – mIPO NLS-binding domain + nucleoplasmin
    
  • 4htv – mIPO NLS-binding domain + capsid protein
    
  • 4ba3 – mIPO NLS-binding domain + A89NLS
    
  • 3zio, 3zip, 3ziq, 3zir – mIPO NLS-binding domain + minor site-specific NLS
    
  • 3zin – mIPO NLS-binding domain + nucleolar RNA helicase
    
• IPO-α 2 complex with protein
  • 3fex, 3fey – mIPO NLS-binding domain + nuclear CAP-binding protein
    
• IPO-α 3
  • 4uae – hIPO NLS-binding domain + influenza RNA polymerase
    
• IPO-α 6
  • 4u2x – hIPO C terminal + ebola VP24
    
• IPO-α 7
  • 4uad – hIPO NLS-binding domain + influenza RNA polymerase
    
• IPO-β
  • 4xrk – IPO – Chaetomium thermophilum
    
• IPO-β 1 (karyopherin β 1)
  • 3nd2 – yIPO
    
  • 1gcj – mIPO N terminal
    
• IPO-β 1 complex with protein
  • 1qgx, 1qgr – hIPO + IPO-α 2 IBB domain
    
  • 1ibr – hIPO + GTPase Ran
    
  • 2bku, 3ea5 – yIPO + GTPase Ran
    
  • 1f59, 1o6p, 1o6o – hIPO + FXFG nucleoporin repeats
    
  • 1m5n – hIPO HEAT repeats 1-11 + parathyroid hormone-related protein NLS peptide
    
  • 2p8q, 2q5d, 2qna, 3lww – hIPO + RNA U transporter N terminal
    
  • 1qgr, 3w5k – hIPO + zinc finger protein SNAI1
    
  • 5owu – yIPO + Nup1
    
  • 1ukl – mIPO + SREBP-2
    
• IPO-β 2 (Transportin 1)
  • 2z5j, 2qmr – hIPO
    
• IPO-β 2 complex with protein
  • 2h4m, 2ot8, 2z5n – hIPO + hnRNP peptide
    
  • 2z5k, 2z5m – hIPO + nuclear RNA export factor peptide
    
  • 2z5o – hIPO + JKTBP peptide
    
  • 4fdd, 4jlq, 4oo6 – hIPO + RNA binding protein peptide
    
  • 4fq3 – hIPO + FUS peptide
    
  • 5tqc – hIPO + RPL4 peptide
    
  • 5j3v – hIPO + histone H3 peptide
    
• IPO-β 3 (Karyopherin β 3)
  • 3w3t – yIPO
    
  • 3w3u, 3w3v – yIPO (mutant)
    
  • 3w3w – yIPO + STE12P
    
  • 3w3x – yIPO + PHO4
    
  • 3w3y – yIPO + Nup53P
    
  • 3w3z – yIPO + RANGTP
    
  • 5h2v – yIPO + ubiquitin-like specific protease
    
  • 4zj7 – yIPO + CDC14
    
• IPO-12 (Transportin-3)
  • 4c0p – hIPO
    
  • 4c0o – hIPO + serine/arginine-rich splicing factor
    
  • 4c0q, 4ol0 – hIPO + GTPase Ran
    
• IPO-13 (karyopherin 13)
  • 2x19 – hIPO + GTPase Ran
    
  • 2xwu – hIPO + UBC9
    
  • 3zjy – hIPO + GTPase Ran + EIF-1A
    

Proteopedia Page Contributors and Editors (what is this?)

Michal Harel, Joel L. Sussman