title: Increased basal insulin secretion in Pdzd2-deficient mice.
abstract: Expression of the multi-PDZ protein Pdzd2 (PDZ domain-containing protein 2) is enriched in pancreatic islet beta cells, but not in exocrine or alpha cells, suggesting a role for Pdzd2 in the regulation of pancreatic beta-cell function. To explore the in vivo function of Pdzd2, Pdzd2-deficient mice were generated. Homozygous Pdzd2 mutant mice were viable and their gross morphology appeared normal. Interestingly, Pdzd2-deficient mice showed enhanced glucose tolerance in intraperitoneal glucose tolerance tests and their plasma insulin levels indicated increased basal insulin secretion after fasting. Moreover, insulin release from mutant pancreatic islets was found to be twofold higher than from normal islets. To verify the functional defect in vitro, Pdzd2 was depleted in INS-1E cells using two siRNA duplexes. Pdzd2-depleted INS-1E cells also displayed increased insulin secretion at low concentrations of glucose. Our results provide the first evidence that Pdzd2 is required for normal regulation of basal insulin secretion.
authors.affiliation: Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
authors.forename: S W
authors.initials: SW
authors.lastname: Tsang
authors.forename: D
authors.initials: D
authors.lastname: Shao
authors.forename: K S E
authors.initials: KS
authors.lastname: Cheah
authors.forename: K
authors.initials: K
authors.lastname: Okuse
authors.forename: P S
authors.initials: PS
authors.lastname: Leung
authors.forename: K-M
authors.initials: KM
authors.lastname: Yao
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D020868:Gene Silencing; D005951:Glucose Tolerance Test; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype
chemical_list: D001786:Blood Glucose; D015815:Cell Adhesion Molecules; D007328:Insulin; D009419:Nerve Tissue Proteins; C545704:Pdzd2 protein, mouse