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The PDZ protein mupp1 promotes Gi coupling and signaling of the Mt1 melatonin receptor.

Authors
  • Guillaume, Jean-Luc
  • Daulat, Avais M
  • Maurice, Pascal
  • Levoye, Angélique
  • Migaud, Martine
  • Brydon, Lena
  • Malpaux, Benoît
  • Borg-Capra, Catherine
  • Jockers, Ralf
Type
Published Article
Journal
Brain Behav Immun
Publication Date
Jun 13, 2008
Volume
283
Issue
24
Pages
16762–16771
Identifiers
DOI: 10.1074/jbc.M802069200
PMID: 18378672
Source
USPC - SET - SVS
License
Unknown

Abstract

Intracellular signaling events are often organized around PDZ (PSD-95/Drosophila Disc large/ZO-1 homology) domain-containing scaffolding proteins. The ubiquitously expressed multi-PDZ protein MUPP1, which is composed of 13 PDZ domains, has been shown to interact with multiple viral and cellular proteins and to play important roles in receptor targeting and trafficking. In this study, we show that MUPP1 binds to the G protein-coupled MT(1) melatonin receptor and directly regulates its G(i)-dependent signal transduction. Structural determinants involved in this interaction are the PDZ10 domain of MUPP1 and the valine of the canonical class III PDZ domain binding motif DSV of the MT(1) carboxyl terminus. This high affinity interaction (K(d) approximately 4 nm), which is independent of MT(1) activation, occurs in the ovine pars tuberalis of the pituitary expressing both proteins endogenously. Although the disruption of the MT(1)/MUPP1 interaction has no effect on the subcellular localization, trafficking, or degradation of MT(1), it destabilizes the interaction between MT(1) and G(i) and abolishes G(i)-mediated signaling of MT(1). Our findings highlight a previously unappreciated role of PDZ proteins in promoting G protein coupling to receptors.

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