Spinophilin regulates Ca2+ signalling by binding the N-terminal domain of RGS2 and the third intracellular loop of G-protein-coupled receptors

2005 ◽  
Vol 7 (4) ◽  
pp. 405-411 ◽  
Author(s):  
Xinhua Wang ◽  
Weizhong Zeng ◽  
Abigail A. Soyombo ◽  
Wei Tang ◽  
Elliott M. Ross ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Intracellular Loop ◽  
The Third ◽  
Terminal Domain ◽  
Third Intracellular Loop ◽  
G Protein Coupled

scholarly journals Identification of Ciliary Localization Sequences within the Third Intracellular Loop of G Protein-coupled Receptors

2008 ◽  
Vol 19 (4) ◽  
pp. 1540-1547 ◽  
Author(s):  
Nicolas F. Berbari ◽  
Andrew D. Johnson ◽  
Jacqueline S. Lewis ◽  
Candice C. Askwith ◽  
Kirk Mykytyn
Keyword(s):  
G Protein ◽  
Serotonin Receptor ◽  
Primary Cilia ◽  
Consensus Sequence ◽  
G Protein Coupled Receptors ◽  
Intracellular Loop ◽  
The Third ◽  
Third Intracellular Loop ◽  
G Protein Coupled ◽  
Ciliary Localization

Primary cilia are sensory organelles present on most mammalian cells. The functions of cilia are defined by the signaling proteins localized to the ciliary membrane. Certain G protein–coupled receptors (GPCRs), including somatostatin receptor 3 (Sstr3) and serotonin receptor 6 (Htr6), localize to cilia. As Sstr3 and Htr6 are the only somatostatin and serotonin receptor subtypes that localize to cilia, we hypothesized they contain ciliary localization sequences. To test this hypothesis we expressed chimeric receptors containing fragments of Sstr3 and Htr6 in the nonciliary receptors Sstr5 and Htr7, respectively, in ciliated cells. We found the third intracellular loop of Sstr3 or Htr6 is sufficient for ciliary localization. Comparison of these loops revealed a loose consensus sequence. To determine whether this consensus sequence predicts ciliary localization of other GPCRs, we compared it with the third intracellular loop of all human GPCRs. We identified the consensus sequence in melanin-concentrating hormone receptor 1 (Mchr1) and confirmed Mchr1 localizes to primary cilia in vitro and in vivo. Thus, we have identified a putative GPCR ciliary localization sequence and used this sequence to identify a novel ciliary GPCR. As Mchr1 mediates feeding behavior and metabolism, our results implicate ciliary signaling in the regulation of body weight.

scholarly journals Recycling ability of the mouse and the human neurotensin type 2 receptors depends on a single tyrosine residue

2002 ◽  
Vol 115 (1) ◽  
pp. 165-173
Author(s):  
Stéphane Martin ◽  
Jean-Pierre Vincent ◽  
Jean Mazella
Keyword(s):  
G Protein ◽  
Kinase Inhibitor ◽  
Site Directed Mutagenesis ◽  
Tyrosine Residue ◽  
Receptor Recycling ◽  
Intracellular Loop ◽  
Structural Element ◽  
The Third ◽  
Third Intracellular Loop ◽  
G Protein Coupled

Receptor recycling plays a key role in the modulation of cellular responses to extracellular signals. The purpose of this work was to identify residues in G-protein coupled neurotensin receptors that are directly involved in recycling. Both the high affinity receptor-1 (NTR1) and the levocabastine-sensitive NTR2 are internalized after neurotensin binding. Here, we show that only the mouse NTR2 recycled to the plasma membrane, whereas the rat NTR1 and the human NTR2 did not. Using site-directed mutagenesis, we demonstrate that tyrosine 237 in the third intracellular loop is crucial for recycling of the mouse NTR2. We show that the mouse NTR2 is phosphorylated on tyrosine residues by NT. This phosphorylation is essential for receptor recycling since the tyrosine kinase inhibitor genistein blocks this process. The absence of recycling observed with the human NTR2 could be completely explained by the presence of a cysteine instead of a tyrosine in position 237. Indeed, substitution of this cysteine by a tyrosine gave a mutant receptor that has acquired the ability to recycle to the cell surface after neurotensin-induced internalization. This work demonstrates that a single tyrosine residue in the third intracellular loop of a G-protein-coupled receptor is responsible for receptor phosphorylation and represents an essential structural element for receptor recycling.

scholarly journals Down-regulation of PAR1 activity with a pHLIP-based allosteric antagonist induces cancer cell death

2015 ◽  
Vol 472 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Kelly E. Burns ◽  
Damien Thévenin
Keyword(s):  
Cell Death ◽  
Cancer Cells ◽  
G Protein ◽  
Cancer Cell ◽  
Intracellular Loop ◽  
The Third ◽  
Cancer Cell Death ◽  
Third Intracellular Loop ◽  
Ph Dependent ◽  
G Protein Coupled

A pH(Low) Insertion Peptide (pHLIP)-based construct derived from the third intracellular loop (i3) of a G protein-coupled receptor (GPCR) induces a concentration- and pH-dependent cytotoxicity in cancer cells by down-regulating receptor activity. This strategy allows for a more selective intracellular delivery than current approaches.

scholarly journals Identification of a Novel Family of Targets of PYK2 Related to Drosophila Retinal Degeneration B (rdgB) Protein

1999 ◽  
Vol 19 (3) ◽  
pp. 2278-2288 ◽  
Author(s):  
Sima Lev ◽  
John Hernandez ◽  
Ricardo Martinez ◽  
Alon Chen ◽  
Greg Plowman ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Retinal Degeneration ◽  
G Protein ◽  
Binding Proteins ◽  
G Protein Coupled Receptors ◽  
Sequence Motif ◽  
Phosphoinositide Metabolism ◽  
Amino Terminal ◽  
Terminal Domain ◽  
G Protein Coupled

ABSTRACT The protein tyrosine kinase PYK2 has been implicated in signaling pathways activated by G-protein-coupled receptors, intracellular calcium, and stress signals. Here we describe the molecular cloning and characterization of a novel family of PYK2-binding proteins designated Nirs (PYK2 N-terminal domain-interacting receptors). The three Nir proteins (Nir1, Nir2, and Nir3) bind to the amino-terminal domain of PYK2 via a conserved sequence motif located in the carboxy terminus. The primary structures of Nirs reveal six putative transmembrane domains, a region homologous to phosphatidylinositol (PI) transfer protein, and an acidic domain. The Nir proteins are the human homologues of the Drosophila retinal degeneration B protein (rdgB), a protein implicated in the visual transduction pathway in flies. We demonstrate that Nirs are calcium-binding proteins that exhibit PI transfer activity in vivo. Activation of PYK2 by agents that elevate intracellular calcium or by phorbol ester induce tyrosine phosphorylation of Nirs. Moreover, PYK2 and Nirs exhibit similar expression patterns in several regions of the brain and retina. In addition, PYK2-Nir complexes are detected in lysates prepared from cultured cells or from brain tissues. Finally, the Nir1-encoding gene is located at human chromosome 17p13.1, in proximity to a locus responsible for several human retinal diseases. We propose that the Nir and rdgB proteins represent a new family of evolutionarily conserved PYK2-binding proteins that play a role in the control of calcium and phosphoinositide metabolism downstream of G-protein-coupled receptors.

Sign in / Sign up

Export Citation Format

Share Document