The PAS domain serine/threonine kinase PASKIN, or PAS kinase, links energy flux and protein synthesis in yeast and regulates glycogen synthase in mammals. A recent report suggested that PASKIN mRNA, protein and kinase activity are increased in pancreatic islet b-cells under hyperglycemic conditions and that PASKIN is necessary for insulin gene expression. We generated Paskin knock-out mice by targeted replacement of the kinase domain by b-galactosidase reporter activity. Here we show that no X-Gal staining was observed in islet b-cells derived from Paskin knock-out mice, irrespective of the glucose concentration, whereas adenoviral expression of the lacZ gene in b-cells showed strong X-Gal staining. No induction of PASKIN mRNA could be detected in islet b-cells. However, glucose stimulation led to PASKIN-independent induction of insulin mRNA levels and insulin secretion. Finally, blood glucose levels and blood glucose tolerance following i.p. glucose injection were indistinguishable between Paskin wild-type and knock-out mice. These results suggest that Paskin gene expression is not induced by glucose in pancreatic b-cells and that glucose- stimulated insulin expression is independent of PASKIN.