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Protein Kinase C (Pkc)-δ Mediates Arginine-Induced Glucagon Secretion in Pancreatic α-Cells

Norikiyo Honzawa1,2, Kei Fujimoto3, Masaki Kobayashi2

  • 1Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Jikei University School of Medicine, 3-25-8 Nishishinbashi, Minato-ku, Tokyo 105-8461, Japan.

International Journal of Molecular Sciences
|April 12, 2022
PubMed

Insights

Protein kinase C delta (Pkcδ) is crucial for regulating glucagon secretion in pancreatic alpha-cells. This study reveals Pkcδ

Area of Science:

  • Endocrinology
  • Molecular Biology
  • Diabetes Pathophysiology

Background:

  • Type 2 diabetes involves complex dysregulation of insulin and glucagon.
  • Protein kinase C delta (Pkcδ) is a serine-threonine kinase implicated in cell death and proliferation.
  • The specific role of Pkcδ in pancreatic alpha-cell glucagon secretion is not well understood.

Purpose of the Study:

  • To investigate the physiological function of Pkcδ in regulating glucagon secretion from pancreatic alpha-cells.
  • To determine if Pkcδ plays a role in amino acid-stimulated glucagon release.

Main Methods:

  • Utilized Pkcδ-knockdown InR1G9 cells, a glucagon-secreting cell line.
  • Employed pancreatic alpha-cell-specific Pkcδ-knockout (αPkcδKO) mice and their isolated islets.
  • Measured glucagon secretion in response to arginine stimulation.

Main Results:

  • Knockdown of Pkcδ in InR1G9 cells diminished basal glucagon secretion.
  • Arginine stimulation led to increased Pkcδ phosphorylation at Thr505, indicating activation.
  • Pkcδ knockdown and knockout significantly reduced arginine-induced glucagon secretion in both cell lines and in vivo models.

Conclusions:

  • Pkcδ is essential for mediating arginine-induced glucagon secretion in pancreatic alpha-cells.
  • These findings elucidate a key molecular mechanism in amino acid-stimulated glucagon release.
  • Targeting Pkcδ presents a potential therapeutic strategy for novel antidiabetic drug development.
Keywords:
arginineglucagonpancreatic α-cellprotein kinase C-δ

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