A compound C-terminal nuclear localization signal of human SA2 stromalin

Acta Biochim Pol. 2015;62(2):215-9. doi: 10.18388/abp.2014_915. Epub 2015 May 15.

Abstract

Stromalins are evolutionarily conserved multifunctional proteins with the best known function in sister chromatid cohesion. Human SA2 stromalin, likely involved in the establishment of cohesion, contains numerous potential nuclear localization (NLS) and nuclear export signals (NES). Previously we have found that the C-terminus of SA2 contains NLS(s) functional in human cells. However, the identity of this signal remained unclear since three NLS-like sequences are present in that region. Here we analyzed the functionality of these putative signals by expressing GFP-tagged C-terminal part of SA2 or its fragments in a human cell line and in the yeast Saccharomyces cerevisiae. We found that in human cells the nuclear import is dependent on a unique compound di- or tripartite signal containing unusually long linkers between clusters of basic amino acids. Upon expression of the same SA2 fragment in yeast this signal is also functional and can be easily studied in more detail.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Antigens, Nuclear / metabolism*
  • Cell Cycle Proteins
  • Cell Nucleus / metabolism
  • Exportin 1 Protein
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • HeLa Cells
  • Humans
  • Karyopherins / metabolism
  • Molecular Sequence Data
  • Nuclear Localization Signals*
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics

Substances

  • Antigens, Nuclear
  • Cell Cycle Proteins
  • Karyopherins
  • Nuclear Localization Signals
  • Receptors, Cytoplasmic and Nuclear
  • Recombinant Fusion Proteins
  • STAG2 protein, human
  • Green Fluorescent Proteins