Human PAPS synthase isoforms are dynamically regulated enzymes with access to nucleus and cytoplasm

PLoS One. 2012;7(1):e29559. doi: 10.1371/journal.pone.0029559. Epub 2012 Jan 5.


In higher eukaryotes, PAPS synthases are the only enzymes producing the essential sulphate-donor 3'-phospho-adenosine-5'-phosphosulphate (PAPS). Recently, PAPS synthases have been associated with several genetic diseases and retroviral infection. To improve our understanding of their pathobiological functions, we analysed the intracellular localisation of the two human PAPS synthases, PAPSS1 and PAPSS2. For both enzymes, we observed pronounced heterogeneity in their subcellular localisation. PAPSS1 was predominantly nuclear, whereas PAPSS2 localised mainly within the cytoplasm. Treatment with the nuclear export inhibitor leptomycin B had little effect on their localisation. However, a mutagenesis screen revealed an Arg-Arg motif at the kinase interface exhibiting export activity. Notably, both isoforms contain a conserved N-terminal basic Lys-Lys-Xaa-Lys motif indispensable for their nuclear localisation. This nuclear localisation signal was more efficient in PAPSS1 than in PAPSS2. The activities of the identified localisation signals were confirmed by microinjection studies. Collectively, we describe unusual localisation signals of both PAPS synthase isoforms, mobile enzymes capable of executing their function in the cytoplasm as well as in the nucleus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Cell Nucleus / drug effects
  • Cell Nucleus / enzymology*
  • Conserved Sequence / genetics
  • Cytosol / enzymology
  • Fatty Acids, Unsaturated / pharmacology
  • Green Fluorescent Proteins / metabolism
  • HeLa Cells
  • Humans
  • Isoenzymes / chemistry
  • Isoenzymes / metabolism
  • Karyopherins / metabolism
  • Mice
  • Molecular Sequence Data
  • Molecular Weight
  • Multienzyme Complexes / chemistry
  • Multienzyme Complexes / metabolism*
  • Mutagenesis / drug effects
  • Mutant Proteins / chemistry
  • Mutant Proteins / metabolism
  • Mutation / genetics
  • Nuclear Export Signals / drug effects
  • Nuclear Localization Signals / chemistry
  • Protein Transport / drug effects
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Subcellular Fractions / drug effects
  • Subcellular Fractions / enzymology
  • Sulfate Adenylyltransferase / chemistry
  • Sulfate Adenylyltransferase / metabolism*


  • Fatty Acids, Unsaturated
  • Isoenzymes
  • Karyopherins
  • Multienzyme Complexes
  • Mutant Proteins
  • Nuclear Export Signals
  • Nuclear Localization Signals
  • Receptors, Cytoplasmic and Nuclear
  • Recombinant Fusion Proteins
  • enhanced green fluorescent protein
  • exportin 1 protein
  • Green Fluorescent Proteins
  • PAPS synthetase
  • Sulfate Adenylyltransferase
  • leptomycin B