Abstract
Biological responses to neuropeptides are rapidly attenuated by overlapping mechanisms that include peptide degradation by cell-surface proteases, receptor uncoupling from heterotrimeric G-proteins and receptor endocytosis. We have investigated the mechanisms that terminate the proinflammatory effects of the neuropeptide substance P (SP), which are mediated by the neurokinin 1 receptor (NK1R). Neutral endopeptidase degrades SP in the extracellular fluid and is one of the first mechanisms to terminate signalling. G-protein receptor kinases and second-messenger kinases phosphorylate the NK1R to permit interaction with β-arrestins, which uncouple the receptor from G-proteins to terminate the signal. SP-induces NK1R endocytosis by a β-arrestin-dependent mechanism, which also involves the GTPases dynamin and Rab5a. Endocytosis contributes to desensitization by depleting receptors from the cell surface. Disruption of these mechanisms results in uncontrolled stimulation and disease. Thus the deletion of neutral endopeptidase in mice exacerbates inflammation of many tissues. There are similarities and distinct differences in the mechanisms that regulate signalling by neuropeptide receptors and other G-protein-coupled receptors, in particular those that are activated irreversibly by proteolysis.
Original language | English (US) |
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Pages (from-to) | 419-426 |
Number of pages | 8 |
Journal | Biochemical Society Transactions |
Volume | 28 |
Issue number | 4 |
DOIs | |
State | Published - 2000 |
Keywords
- Arrestins
- Desensitization
- Neutral endopeptidases
- Substance P
ASJC Scopus subject areas
- Biochemistry