Dual regulation of the parathyroid hormone (PTH)/PTH-related peptide receptor signaling by protein kinase C and beta-arrestins

Endocrinology. 2002 Oct;143(10):3854-65. doi: 10.1210/en.2002-220232.

Abstract

We examined here the role of second messenger-dependent kinases and beta-arrestins in short-term regulation of the PTH receptor (PTHR) signaling. The inhibition of protein kinase C (PKC) in COS-7 cells transiently expressing PTHR, led to an approximately 2-fold increase in PTH-stimulated inositol phosphate (IP) and cAMP production. The inhibition of protein kinase A increased cAMP production 1.5-fold without affecting IP signaling. The effects of PKC inhibition on PTHR-mediated G(q) signaling were strongly decreased for a carboxy-terminally truncated PTHR (T480) that is phosphorylation deficient. PKC inhibition was associated with a decrease in agonist-stimulated PTHR phosphorylation and internalization without blocking PTH-dependent mobilization of beta-arrestin2 to the plasma membrane. Overexpression of beta-arrestins strongly decreased the PTHR-mediated IP signal, whereas cAMP production was impaired to a much lower extent. The regulation of PTH-stimulated signals by beta-arrestins was impaired for the truncated T480 receptor. Our data reveal mechanisms at, and distal to, the receptor regulating PTHR-mediated signaling pathways by second messenger-dependent kinases. We conclude that regulation of PTHR-mediated signaling by PKC and beta-arrestins are separable phenomena that both involve the carboxy terminus of the receptor. A major role for PKC and beta-arrestins in preferential regulation of PTHR-mediated G(q) signaling by independent mechanisms at the receptor level was established.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arrestins / pharmacology
  • Arrestins / physiology*
  • COS Cells
  • Cyclic AMP / physiology
  • Inositol Phosphates / physiology
  • Parathyroid Hormone / pharmacology
  • Peptide Fragments / metabolism
  • Phosphotransferases / physiology
  • Protein Kinase C / physiology*
  • Receptor, Parathyroid Hormone, Type 1
  • Receptors, Parathyroid Hormone / chemistry
  • Receptors, Parathyroid Hormone / metabolism
  • Receptors, Parathyroid Hormone / physiology*
  • Second Messenger Systems / physiology
  • Signal Transduction / physiology*
  • beta-Arrestins

Substances

  • Arrestins
  • Inositol Phosphates
  • Parathyroid Hormone
  • Peptide Fragments
  • Receptor, Parathyroid Hormone, Type 1
  • Receptors, Parathyroid Hormone
  • beta-Arrestins
  • Cyclic AMP
  • Phosphotransferases
  • Protein Kinase C