The role of HSP70 on ENPP1 expression and insulin-receptor activation.
Ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) inhibits insulin-receptor (IR) signaling and, when over-expressed, induces insulin resistance in vitro and in vivo. Understanding the regulation of ENPP1 expression may, thus, unravel new molecular mechanisms of insulin resistance. Recent data point to a pivotal role of the ENPP1 3'UTR, in modulating ENPP1 mRNA stability and expression. We sought to identify trans-acting proteins binding the ENPP1-3'UTR and to investigate their role on ENPP1 expression and on IR signaling. By RNA electrophoresis mobility shift analysis and tandem mass spectrometry, we demonstrated the binding of heat shock protein 70 (HSP70) to ENPP1-3'UTR. Through this binding, HSP70 stabilizes ENPP1 mRNA and increases ENPP1 transcript and protein levels. This positive modulation of ENPP1 expression is paralleled by a reduced insulin-induced IR and IRS-1 phosphorylation. Taken together these data suggest that HSP70, by affecting ENPP1 expression, may be a novel mediator of altered insulin signaling.
Marucci
Antonella
A
Research Unit of Diabetes and Endocrine Diseases, Scientific Institute, Poliambulatorio Giovanni Paolo II, Viale Padre Pio, 71013 San Giovanni Rotondo, Italy.
Miscio
Giuseppe
G
Research Unit of Diabetes and Endocrine Diseases, Scientific Institute, Poliambulatorio Giovanni Paolo II, Viale Padre Pio, 71013 San Giovanni Rotondo, Italy.
Padovano
Libera
L
Research Unit of Diabetes and Endocrine Diseases, Scientific Institute, Poliambulatorio Giovanni Paolo II, Viale Padre Pio, 71013 San Giovanni Rotondo, Italy.
Boonyasrisawat
Watip
W
Research Division, Joslin Diabetes Center, Boston, MA, USA.
Florez
Jose C
JC
Department of Medicine, Harvard Medical School, Boston, MA, USA.
Doria
Alessandro
A
Research Division, Joslin Diabetes Center, Boston, MA, USA.
Trischitta
Vincenzo
V
Research Unit of Diabetes and Endocrine Diseases, Scientific Institute, Poliambulatorio Giovanni Paolo II, Viale Padre Pio, 71013 San Giovanni Rotondo, Italy.
Paola
Rosa Di
RD
Research Unit of Diabetes and Endocrine Diseases, Scientific Institute, Poliambulatorio Giovanni Paolo II, Viale Padre Pio, 71013 San Giovanni Rotondo, Italy.
D020413:3' Untranslated Regions / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D024202:Electrophoretic Mobility Shift Assay; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism*; D011972:Receptor, Insulin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053719:Tandem Mass Spectrometry; D014162:Transfection
D020413:3' Untranslated Regions; D018840:HSP70 Heat-Shock Proteins; D007328:Insulin; D011972:Receptor, Insulin; D010727:Phosphoric Diester Hydrolases; C065962:ectonucleotide pyrophosphatase phosphodiesterase 1; D011755:Pyrophosphatases