The human serotonin1A receptor exhibits G-protein-dependent cell surface dynamics

Pucadyil, Thomas J.; Chattopadhyay, Amitabha

doi:10.1007/s10719-006-9008-x

Cited by 19 publications

(8 citation statements)

References 46 publications

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“…In addition, the percentage of the mobile fraction is very high (Ͼ85%) in the three cellular compartments studied. The diffusion characteristics of the sst 2A is similar from those reported for other GPCRs in extrasynaptic sites, such as the serotonin 5HT 1A (Pucadyil and Chattopadhyay, 2007) and dopamine D 1 (Scott et al, 2006) receptors. In spines, although the sst 2A receptor has been shown to potentially interact with scaffolding proteins of the postsynaptic density Shank1 and ProSAP1/CortBP1 (Zitzer et al, 1999a,b), our results indicate that, in resting conditions, only a minor portion of sst 2A receptors might be associated with cytoskeletal anchoring proteins.…”

Section: Discussionsupporting

confidence: 77%

Dynamics of Somatostatin Type 2A Receptor Cargoes in Living Hippocampal Neurons

Lelouvier

Tamagno²,

Kaindl³

et al. 2008

J. Neurosci.

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Despite the large number of G-protein-coupled receptor (GPCR) types expressed in the CNS, little is known about their dynamics in neuronal cells. Dynamic properties of the somatostatin type 2A receptor were therefore examined in resting conditions and after agonist activation in living hippocampal neurons. Using fluorescence recovery after photobleaching experiments, we found that, in absence of ligand, the sst 2A receptor is mobile and laterally and rapidly diffuse in neuronal membranes. We then observed by live-cell imaging that, after agonist activation, membrane-associated receptors induce the recruitment of ␤-arrestin 1-enhanced green fluorescent protein (EGFP) and ␤-arrestin 2-EGFP to the plasma membrane. In addition, ␤-arrestin 1-EGFP translocate to the nucleus, suggesting that this protein could serve as a nuclear messenger for the sst 2A receptor in neurons. Receptors are then recruited to preexisting clathrin coated pits, form clusters that internalize, fuse, and move to a perinuclear compartment that we identified as the trans-Golgi network (TGN), and recycle. Receptor cargoes are transported through a microtubule-dependent process directly from early endosomes/recycling endosomes to the TGN, bypassing the late endosomal compartment. Together, these results provide a comprehensive description of GPCR trafficking in living neurons and provide compelling evidence that GPCR cargoes can recycle through the TGN after endocytosis, a phenomenon that has not been anticipated from studies of non-neuronal cells.

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Section: Discussionsupporting

confidence: 77%

Dynamics of Somatostatin Type 2A Receptor Cargoes in Living Hippocampal Neurons

Lelouvier

Tamagno²,

Kaindl³

et al. 2008

J. Neurosci.

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“…Similarly, the GABA A receptor has been shown to diffuse rapidly within the extrasynaptic membrane (28). Rapid diffusion is not restricted to receptor ion channels, as the G-protein-coupled serotonin 5-HT1a (29) and dopamine D1 (30) receptors also move freely in extrasynaptic membrane. Taken together, the data indicate that GABA B receptors exhibit distinctive diffusion dynamics.…”

Section: Discussionmentioning

confidence: 99%

“…We investigated whether stimulation of GABA B might affect receptor movement, as previous studies have demonstrated that movement of other metabotropic receptors, such as the serotonin 5-HT1a receptor, is greater following agonist stimulation (29,34). We treated cells expressing GABA B1 and GABA B2 with the agonist baclofen and found that baclofen stimulation significantly increased its diffusion rate; the effect of baclofen was prevented by co-treatment with a GABA B antagonist.…”

Section: Discussionmentioning

confidence: 99%

Lateral Diffusion of the GABAB Receptor Is Regulated by the GABAB2 C Terminus

Pooler

McIlhinney

2007

Journal of Biological Chemistry

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GABA B (␥-aminobutyric acid, type B) is a heterodimeric G-protein-coupled receptor. The GABA B1 subunit, which contains an endoplasmic reticulum retention sequence, is only transported to the cell surface when it is associated with the GABA B2 subunit. Fluorescence recovery after photobleaching studies in transfected COS-7 cells and hippocampal neurons revealed that GABA B2 diffuses slowly within the plasma membrane whether expressed alone or with the GABA B1 subunit. Treatment of cells with brefeldin A revealed that GABA B2 moves freely within the endoplasmic reticulum, suggesting that slow movement of GABA B2 is a result of its plasma membrane insertion. Disruption of the cytoskeleton did not affect the mobility of GABA B2 , indicating that its restricted diffusion is not due to direct interactions with actin or tubulin. To determine whether the C terminus of GABA B2 regulates its diffusion, this region of the subunit was attached to the lymphocyte membrane protein, CD2, which then exhibited a slower rate of lateral diffusion. Furthermore, co-expression of a cytoplasmically expressed soluble form of the GABA B2 C terminus increased movement of the GABA B2 subunit. We constructed forms of GABA B2 with various C-terminal truncations. Truncation of GABA B2 after residue 862, but not residue 886, caused a dramatic increase in its mobility, suggesting that the region between these two residues is critical for restricting GABA B2 diffusion. Finally, we investigated whether activation of GABA B might modulate its movement. Treatment of COS-7 cells with the GABA B receptor agonist baclofen significantly increased its mobile fraction. These data show that the restricted movement of GABA B at the cell surface is regulated by a region within its C terminus.GABA B receptors are metabotropic receptors for the inhibitory neurotransmitter ␥ aminobutyric acid (GABA).2 Pre-and post-synaptic GABA B receptors are coupled to inhibitory G-proteins and can regulate neurotransmission via several mechanisms, including modulation of adenylyl cyclase (1), inhibition of voltage-gated Ca 2ϩ channels (2), and modulation of K ϩ channels (3, 4). Formation of a functional receptor requires the heterodimerization of two subunits, GABA B1 and GABA B2 (5). Previous work has demonstrated that the stable assembly of these subunits occurs, to some extent, via association of coiled-coil domains within their C termini (6). The subunits appear to serve different functions within the fully formed receptor. GABA B1 contains the agonist binding site on its large extracellular N terminus, and the affinity of this site for agonists is increased following heterodimerization with GABA B2 (7). The GABA B2 subunit contains intracellular loops that couple the receptor to the G-protein (8 -10).Heterodimerization of the GABA B subunits is important not only for proper receptor function but also for forward trafficking of the receptor to the cell surface (5, 7). In the absence of GABA B2 , the GABA B1 subunit is retained within the endoplasmic reticulum due to th...

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“…In addition, stimulation by serotonin has not been found to result in any significant difference in the fluorescence distribution of serotonin 1A receptor fused to EYFP ). However, a significant increase in the lateral mobility of the serotonin 1A receptor fused to EYFP has been shown using fluorescence recovery after photobleaching (FRAP) Pucadyil and Chattopadhyay 2007c). Based on all these results, it appears that while the membrane dynamics (diffusion) of the serotonin 1A receptor could be modulated in the presence of serotonin, fluorescence distribution and detergent insolubility measurements do not indicate any apparent cell surface reorganization of the receptor when stimulated by serotonin.…”

Section: Monitoring Membrane Organization Of the Serotonin 1a Receptomentioning

confidence: 96%

Membrane Organization and Function of the Serotonin1A Receptor

Kalipatnapu

Chattopadhyay

2007

Cell Mol Neurobiol

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(1) The serotonin(1A) receptor is a G-protein coupled receptor involved in several cognitive, behavioral, and developmental functions. It binds the neurotransmitter serotonin and signals across the membrane through its interactions with heterotrimeric G-proteins. (2) Lipid-protein interactions in membranes play an important role in the assembly, stability, and function of membrane proteins. The role of membrane environment in serotonin(1A) receptor function is beginning to be addressed by exploring the consequences of lipid manipulations on the ligand binding and G-protein coupling of serotonin(1A) receptors, the ability to functionally solubilize the serotonin(1A) receptor, and the factors influencing the membrane organization of the serotonin(1A) receptor. (3) Recent developments involving the application of detergent-based and detergent-free approaches to understand the membrane organization of the serotonin(1A) receptor under conditions of ligand activation and modulation of membrane lipid content, with an emphasis on membrane cholesterol, are described.

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The human serotonin1A receptor exhibits G-protein-dependent cell surface dynamics

Cited by 19 publications

References 46 publications

Dynamics of Somatostatin Type 2A Receptor Cargoes in Living Hippocampal Neurons

Dynamics of Somatostatin Type 2A Receptor Cargoes in Living Hippocampal Neurons

Lateral Diffusion of the GABAB Receptor Is Regulated by the GABAB2 C Terminus

Membrane Organization and Function of the Serotonin1A Receptor

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