Human PAPS Synthase Isoforms Are Dynamically Regulated Enzymes with Access to Nucleus and Cytoplasm

Elisabeth Schröder,Andrey A Eremeev,Shirley K Knauer,Daniel Grum,Lena Gebel,Peter Bayer,Jessica Morgner,Jonathan W Mueller,Annalisa Pastore

doi:10.1371/journal.pone.0029559

Elisabeth Schröder, Andrey A Eremeev + Show 7 more

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https://doi.org/10.1371/journal.pone.0029559

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Journal: PloS one	Publication Date: Jan 5, 2012
Citations: 74	License type: CC BY 4.0

Affiliation: University of Duisburg-Essen

Abstract

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.

Highlights

Central to all biological sulphation reactions in eukaryotes is the conversion of the very stable oxy-anion sulphate to the highenergy sulphate donor 39-phospho-adenosine-59-phosphosulphate (PAPS)
They are fed by only two PAPS producing enzymes in vertebrates – the bifunctional PAPS synthases 1 and 2 (PAPSS1/2) [8,9] consisting of an N-terminal adenosine-59-phosphosulphate (APS) kinase domain and a C-terminal ATP sulphurylase domain connected by a short irregular linker [10]
The general trend in all our experiments was that PAPSS1-EGFP was predominantly located to the nucleus, and more of the PAPSS2-EGFP fluorescence could be detected in the cytosol

Summary

Introduction

Central to all biological sulphation reactions in eukaryotes is the conversion of the very stable oxy-anion sulphate to the highenergy sulphate donor 39-phospho-adenosine-59-phosphosulphate (PAPS). A vast number of sulphotransferases has been described with 53 current entries for human enzymes in Entrez Gene [2] Part of this enzymatic apparatus is required to create the highly complex extracellular sulphated carbohydrates [3]. The many and diverse sulphotransferases are localised to the Golgi apparatus [5], the cytoplasm [6] and even the nucleus [7] They are fed by only two PAPS producing enzymes in vertebrates – the bifunctional PAPS synthases 1 and 2 (PAPSS1/2) [8,9] consisting of an N-terminal adenosine-59-phosphosulphate (APS) kinase domain and a C-terminal ATP sulphurylase domain connected by a short irregular linker [10]. PAPS synthases have been implicated in steroid metabolism [13] and hepatitis B infection [14]

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