TY - JOUR
T1 - Human Mutation within Per-Arnt-Sim (PAS) Domain-containing Protein Kinase (PASK) Causes Basal Insulin Hypersecretion
AU - Semplici, Francesca
AU - Vaxillaire, Martine
AU - Fogarty, Sarah
AU - Semache, Meriem
AU - Bonnefond, Amelie
AU - Fontes, Ghislaine
AU - Philippe, Julien
AU - Meur, Gargi
AU - Diraison, Frederique
AU - Sessions, Richard B.
AU - Rutter, Jared
AU - Poitout, Vincent
AU - Froguel, Philippe
AU - Rutter, Guy A.
PY - 2011/12/23
Y1 - 2011/12/23
N2 - PAS kinase (PASK) is a glucose-regulated protein kinase involved in the control of pancreatic islet hormone release and insulin sensitivity. We aimed here to identify mutations in the PASK gene that may be associated with young-onset diabetes in humans. We screened 18 diabetic probands with unelucidated maturity-onset diabetes of the young (MODY). We identified two rare nonsynonymous mutations in the PASK gene (p.L1051V and p.G1117E), each of which was found in a single MODY family. Wild type or mutant PASKs were expressed in HEK 293 cells. Kinase activity of the affinity-purified proteins was assayed as autophosphorylation at amino acid Thr(307) or against an Ugp1p-derived peptide. Whereas the PASK p.G1117E mutant displayed a similar to 25% increase with respect to wild type PASK in the extent of autophosphorylation, and a similar to 2-fold increase in kinase activity toward exogenous substrates, the activity of the p.L1051V mutant was unchanged. Amino acid Gly(1117) is located in an alpha helical region opposing the active site of PASK and may elicit either: (a) a conformational change that increases catalytic efficiency or (b) a diminished inhibitory interaction with the PAS domain. Mouse islets were therefore infected with adenoviruses expressing wild type or mutant PASK and the regulation of insulin secretion was examined. PASK p.G1117E-infected islets displayed a 4-fold decrease in glucose-stimulated (16.7 versus 3 mM) insulin secretion, chiefly reflecting a 4.5-fold increase in insulin release at low glucose. In summary, we have characterized a rare mutation (p.G1117E) in the PASK gene from a young-onset diabetes family, which modulates glucose-stimulated insulin secretion.
AB - PAS kinase (PASK) is a glucose-regulated protein kinase involved in the control of pancreatic islet hormone release and insulin sensitivity. We aimed here to identify mutations in the PASK gene that may be associated with young-onset diabetes in humans. We screened 18 diabetic probands with unelucidated maturity-onset diabetes of the young (MODY). We identified two rare nonsynonymous mutations in the PASK gene (p.L1051V and p.G1117E), each of which was found in a single MODY family. Wild type or mutant PASKs were expressed in HEK 293 cells. Kinase activity of the affinity-purified proteins was assayed as autophosphorylation at amino acid Thr(307) or against an Ugp1p-derived peptide. Whereas the PASK p.G1117E mutant displayed a similar to 25% increase with respect to wild type PASK in the extent of autophosphorylation, and a similar to 2-fold increase in kinase activity toward exogenous substrates, the activity of the p.L1051V mutant was unchanged. Amino acid Gly(1117) is located in an alpha helical region opposing the active site of PASK and may elicit either: (a) a conformational change that increases catalytic efficiency or (b) a diminished inhibitory interaction with the PAS domain. Mouse islets were therefore infected with adenoviruses expressing wild type or mutant PASK and the regulation of insulin secretion was examined. PASK p.G1117E-infected islets displayed a 4-fold decrease in glucose-stimulated (16.7 versus 3 mM) insulin secretion, chiefly reflecting a 4.5-fold increase in insulin release at low glucose. In summary, we have characterized a rare mutation (p.G1117E) in the PASK gene from a young-onset diabetes family, which modulates glucose-stimulated insulin secretion.
U2 - 10.1074/jbc.M111.254995
DO - 10.1074/jbc.M111.254995
M3 - Article (Academic Journal)
C2 - 22065581
SN - 0021-9258
VL - 286
SP - 44005
EP - 44014
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 51
ER -