Deletion of CDKAL1 affects mitochondrial ATP generation and first-phase insulin exocytosis

PLoS One. 2010 Dec 9;5(12):e15553. doi: 10.1371/journal.pone.0015553.


Background: A variant of the CDKAL1 gene was reported to be associated with type 2 diabetes and reduced insulin release in humans; however, the role of CDKAL1 in β cells is largely unknown. Therefore, to determine the role of CDKAL1 in insulin release from β cells, we studied insulin release profiles in CDKAL1 gene knockout (CDKAL1 KO) mice.

Principal findings: Total internal reflection fluorescence imaging of CDKAL1 KO β cells showed that the number of fusion events during first-phase insulin release was reduced. However, there was no significant difference in the number of fusion events during second-phase release or high K(+)-induced release between WT and KO cells. CDKAL1 deletion resulted in a delayed and slow increase in cytosolic free Ca(2+) concentration during high glucose stimulation. Patch-clamp experiments revealed that the responsiveness of ATP-sensitive K(+) (K(ATP)) channels to glucose was blunted in KO cells. In addition, glucose-induced ATP generation was impaired. Although CDKAL1 is homologous to cyclin-dependent kinase 5 (CDK5) regulatory subunit-associated protein 1, there was no difference in the kinase activity of CDK5 between WT and CDKAL1 KO islets.

Conclusions/significance: We provide the first report describing the function of CDKAL1 in β cells. Our results indicate that CDKAL1 controls first-phase insulin exocytosis in β cells by facilitating ATP generation, K(ATP) channel responsiveness and the subsequent activity of Ca(2+) channels through pathways other than CDK5-mediated regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Animals
  • B-Lymphocytes / metabolism
  • Cyclin-Dependent Kinase 5 / genetics*
  • Cyclin-Dependent Kinase 5 / metabolism
  • Cytosol / metabolism
  • Diabetes Mellitus, Type 2 / metabolism
  • Exocytosis
  • Genetic Variation
  • Glucose / metabolism
  • Insulin / metabolism*
  • Mice
  • Mice, Knockout
  • Mitochondria / metabolism*
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / physiology
  • Patch-Clamp Techniques
  • Potassium / chemistry
  • tRNA Methyltransferases


  • Insulin
  • Nerve Tissue Proteins
  • Adenosine Triphosphate
  • tRNA Methyltransferases
  • Cyclin-Dependent Kinase 5
  • Cdk5 protein, mouse
  • CDKAL1 protein, mouse
  • Glucose
  • Potassium