Kinase suppressor of Ras 1 and Exo70 promote fatty acid-stimulated neurotensin secretion through ERK1/2 signaling

PLoS One. 2019 Mar 27;14(3):e0211134. doi: 10.1371/journal.pone.0211134. eCollection 2019.

Abstract

Neurotensin is a peptide hormone released from enteroendocrine cells in the small intestine in response to fat ingestion. Although the mechanisms regulating neurotensin secretion are still incompletely understood, our recent findings implicate a role for extracellular signal-regulated kinase 1 and 2 as positive regulators of free fatty acid-stimulated neurotensin secretion. Previous studies have shown that kinase suppressor of Ras 1 acts as a molecular scaffold of the Raf/MEK/extracellular signal-regulated kinase 1 and 2 kinase cascade and regulates intensity and duration of extracellular signal-regulated kinase 1 and 2 signaling. Here, we demonstrate that inhibition of kinase suppressor of Ras 1 attenuates neurotensin secretion and extracellular signal-regulated kinase 1 and 2 signaling in human endocrine cells. Conversely, we show that overexpression of kinase suppressor of Ras 1 enhances neurotensin secretion and extracellular signal-regulated kinase 1 and 2 signaling. We also show that inhibition of extracellular signal-regulated kinase 2 and exocyst complex component 70, a substrate of extracellular signal-regulated kinase 2 and mediator of secretory vesicle exocytosis, potently inhibits basal and docosahexaenoic acid-stimulated neurotensin secretion, whereas overexpression of exocyst complex component 70 enhances basal and docosahexaenoic acid-stimulated neurotensin secretion. Together, our findings demonstrate a role for kinase suppressor of Ras 1 as a positive regulator of neurotensin secretion from human endocrine cells and indicate that this effect is mediated by the extracellular signal-regulated kinase 1 and 2 signaling pathway. Moreover, we reveal a novel role for exocyst complex component 70 in regulation of neurotensin vesicle exocytosis through its interaction with the extracellular signal-regulated kinase 1 and 2 signaling pathway.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Line
  • Cell Line, Tumor
  • Endocrine Cells / metabolism
  • Enteroendocrine Cells / metabolism
  • Exocytosis
  • Fatty Acids / metabolism
  • Humans
  • MAP Kinase Signaling System*
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Mitogen-Activated Protein Kinases / metabolism
  • Neurotensin / metabolism*
  • Protein Binding
  • Protein Kinases / metabolism*
  • Secretory Vesicles / metabolism
  • Signal Transduction
  • Vesicular Transport Proteins / metabolism*

Substances

  • EXOC7 protein, human
  • Fatty Acids
  • Vesicular Transport Proteins
  • Neurotensin
  • Protein Kinases
  • KSR-1 protein kinase
  • MAPK1 protein, human
  • MAPK3 protein, human
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases