Pancreatic beta-cell growth and survival in the onset of type 2 diabetes: a role for protein kinase B in the Akt?

Am J Physiol Endocrinol Metab. 2004 Aug;287(2):E192-8. doi: 10.1152/ajpendo.00031.2004.

Abstract

The control of pancreatic beta-cell growth and survival in the adult plays a pivotal role in the pathogenesis of type 2 diabetes. In certain insulin-resistant states, such as obesity, the increased insulin-secretory demand can often be compensated for by an increase in beta-cell mass, so that the onset of type 2 diabetes is avoided. This is why approximately two-thirds of obese individuals do not progress to type 2 diabetes. However, the remaining one-third of obese subjects that do acquire type 2 diabetes do so because they have inadequate compensatory beta-cell mass and function. As such, type 2 diabetes is a disease of insulin insufficiency. Indeed, it is now realized that, in the vast majority of type 2 diabetes cases, there is a decreased beta-cell mass caused by a marked increase in beta-cell apoptosis that outweighs rates of beta-cell mitogenesis and neogenesis. Thus a means of promoting beta-cell survival has potential therapeutic implications for treating type 2 diabetes. However, understanding the control of beta-cell growth and survival at the molecular level is a relatively new subject area of research and still in its infancy. Notwithstanding, recent advances have implicated signal transduction via insulin receptor substrate-2 (IRS-2) and downstream via protein kinase B (PKB, also known as Akt) as critical to the control of beta-cell survival. In this review, we highlight the mechanism of IRS-2, PKB, and anti-apoptotic PKB substrate control of beta-cell growth and survival, and we discuss whether these may be targeted therapeutically to delay the onset of type 2 diabetes.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Adult
  • Animals
  • Apoptosis / physiology
  • Cell Survival
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / physiopathology*
  • Diabetes Mellitus, Type 2 / therapy
  • Humans
  • Insulin Receptor Substrate Proteins
  • Intracellular Signaling Peptides and Proteins
  • Islets of Langerhans / enzymology*
  • Islets of Langerhans / growth & development*
  • Islets of Langerhans / pathology
  • Mice
  • Obesity / complications
  • Obesity / physiopathology*
  • Phosphoproteins / metabolism*
  • Protein Serine-Threonine Kinases / metabolism*
  • Protein Serine-Threonine Kinases / therapeutic use
  • Protein-Tyrosine Kinases / metabolism*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins / therapeutic use
  • Proto-Oncogene Proteins c-akt
  • Rats
  • Signal Transduction

Substances

  • IRS2 protein, human
  • Insulin Receptor Substrate Proteins
  • Intracellular Signaling Peptides and Proteins
  • Irs2 protein, mouse
  • Irs2 protein, rat
  • Phosphoproteins
  • Proto-Oncogene Proteins
  • Protein-Tyrosine Kinases
  • AKT1 protein, human
  • Akt1 protein, rat
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt