Diabetologie und Stoffwechsel 2018; 13(S 01): S22
DOI: 10.1055/s-0038-1641820
Poster
Typ-2-Diabetes – Pathophysiologie II
Georg Thieme Verlag KG Stuttgart · New York

hnRNP A2/B1 as a novel post-transcriptional regulator of insulin expression in β-cells

J Vasiljevic
1   Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
2   Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus and Faculty of Medicine of the TU Dresden, Dresden, Germany
3   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
,
C Niehage
4   Biotechnology Center, TU Dresden, Dresden, Germany
,
D Vasiljevic
5   Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
,
A Soenmez
1   Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
2   Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus and Faculty of Medicine of the TU Dresden, Dresden, Germany
3   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
,
C Wegbrod
1   Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
2   Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus and Faculty of Medicine of the TU Dresden, Dresden, Germany
3   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
,
M Selbach
5   Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
6   Charité – Universitätsmedizin Berlin, Berlin, Germany
,
B Hoflack
4   Biotechnology Center, TU Dresden, Dresden, Germany
,
M Solimena
1   Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
2   Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus and Faculty of Medicine of the TU Dresden, Dresden, Germany
3   German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
26 April 2018 (online)

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Questions:

Glucose stimulation of β-cells rapidly increases insulin biosynthesis and secretory granule (SG) biogenesis. This increase occurs without affecting the levels of mRNAs coding SG components, pointing to post-transcriptional regulation. Several RNA-binding proteins (RBP) that regulate the stability and translation of these transcripts encoding are known, but a comprehensive view of their binding in resting and stimulated conditions is still missing.

Methods:

Cytosolic extracts from rested and glucose stimulated MIN6 cells were used for in vitro RNA pull-downs with the biotinylated 5'-UTRs of Ins1, Ins2, spliced Ins2, PC2 and ICA512 mRNAs. γ-tubulin mRNA 5'-UTR was used as a control. The isolated proteins were identified by mass spectrometry.

Results:

We identified several novel RBPs that interact with mRNAs coding for SG proteins in β-cells. These mRNAs are bound to one set of these RBPs in resting conditions and to a different set of RBPs upon glucose stimulation. One of the novel RBPs, hnRNP A2/B1, was shown to be post-transcriptionally upregulated by glucose, which induced its translocation into the nucleus. hnRNP A2/B1 binding to the 5'-UTR of mIns1 mRNA was confirmed, and its knock-out in MIN6 cells reduced the levels of Ins1 mRNA, proinsulin and insulin.

Conclusions:

To our knowledge, this is the first unbiased proteomics study for the characterization of glucose-induced changes in RBPs associated with mRNAs for SG cargoes. Our results indicate that hnRNP A2/B1 regulates the stability of Ins1 mRNA. Taken together, our data provide further insight into the mechanisms of glucose-induced insulin biosynthesis and SG biogenesis.