Cross-talk between snurportin1 subdomains

Jason K. Ospina, Graydon Bennett Gonsalvez, Janna Bednenko, Edward Darzynkiewicz, Larry Gerace, A. Gregory Matera

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The initial steps of spliceosomal small nuclear ribonucleoprotein (snRNP) maturation take place in the cytoplasm. After formation of an Sm-core and a trimethylguanosine (TMG) cap, the RNPs are transported into the nucleus via the import adaptor snurportin1 (SPN) and the import receptor importin-β. To better understand this process, we identified SPN residues that are required to mediate interactions with TMG caps, importin-β, and the export receptor, exportin1 (Xpo1/Crm1). Mutation of a single arginine residue within the importin-β binding domain (IBB) disrupted the interaction with importin-β, but preserved the ability of SPN to bind Xpo1 or TMG caps. Nuclear transport assays showed that this IBB mutant is deficient for snRNP import but that import can be rescued by addition of purified survival of motor neurons (SMN) protein complexes. Conserved tryptophan residues outside of the IBB are required for TMG binding. However, SPN can be imported into the nucleus without cargo. Interestingly, SPN targets to Cajal bodies when U2 but not U1 snRNPs are imported as cargo. SPN also relocalizes to Cajal bodies upon treatment with leptomycin B. Finally, we uncovered an interaction between the N- and C-terminal domains of SPN, suggesting an autoregulatory function similar to that of importin-α.

Original languageEnglish (US)
Pages (from-to)4660-4671
Number of pages12
JournalMolecular Biology of the Cell
Volume16
Issue number10
DOIs
StatePublished - Oct 1 2005

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Karyopherins
Small Nuclear Ribonucleoproteins
Cell Nucleus Active Transport
SMN Complex Proteins
Tryptophan
Arginine
Cytoplasm
Mutation

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

Cite this

Ospina, J. K., Gonsalvez, G. B., Bednenko, J., Darzynkiewicz, E., Gerace, L., & Matera, A. G. (2005). Cross-talk between snurportin1 subdomains. Molecular Biology of the Cell, 16(10), 4660-4671. https://doi.org/10.1091/mbc.E05-04-0316

Cross-talk between snurportin1 subdomains. / Ospina, Jason K.; Gonsalvez, Graydon Bennett; Bednenko, Janna; Darzynkiewicz, Edward; Gerace, Larry; Matera, A. Gregory.

In: Molecular Biology of the Cell, Vol. 16, No. 10, 01.10.2005, p. 4660-4671.

Research output: Contribution to journalArticle

Ospina, JK, Gonsalvez, GB, Bednenko, J, Darzynkiewicz, E, Gerace, L & Matera, AG 2005, 'Cross-talk between snurportin1 subdomains', Molecular Biology of the Cell, vol. 16, no. 10, pp. 4660-4671. https://doi.org/10.1091/mbc.E05-04-0316
Ospina JK, Gonsalvez GB, Bednenko J, Darzynkiewicz E, Gerace L, Matera AG. Cross-talk between snurportin1 subdomains. Molecular Biology of the Cell. 2005 Oct 1;16(10):4660-4671. https://doi.org/10.1091/mbc.E05-04-0316
Ospina, Jason K. ; Gonsalvez, Graydon Bennett ; Bednenko, Janna ; Darzynkiewicz, Edward ; Gerace, Larry ; Matera, A. Gregory. / Cross-talk between snurportin1 subdomains. In: Molecular Biology of the Cell. 2005 ; Vol. 16, No. 10. pp. 4660-4671.
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