Identification Methods of G Protein-Coupled Receptors

Author(s):  
Meriem Zekri ◽  
Karima Alem ◽  
Labiba Souici-Meslati

The G protein-coupled receptors (GPCRs) include one of the largest and most important families of multifunctional proteins known to molecular biology. They play a key role in cell signaling networks that regulate many physiological processes, such as vision, smell, taste, neurotransmission, secretion, immune responses, metabolism, and cell growth. These proteins are thus very important for understanding human physiology and they are involved in several diseases. Therefore, many efforts in pharmaceutical research are to understand their structures and functions, which is not an easy task, because although thousands GPCR sequences are known, many of them remain orphans. To remedy this, many methods have been developed using methods such as statistics, machine learning algorithms, and bio-inspired approaches. In this article, the authors review the approaches used to develop algorithms for classification GPCRs by trying to highlight the strengths and weaknesses of these different approaches and providing a comparison of their performances.


2018 ◽  
Vol 19 (12) ◽  
pp. 3912 ◽  
Author(s):  
Zhengbing Wang ◽  
Wenwu Zhou ◽  
Muhammad Hameed ◽  
Jiali Liu ◽  
Xinnian Zeng

Neuropeptides are endogenous active substances that widely exist in multicellular biological nerve tissue and participate in the function of the nervous system, and most of them act on neuropeptide receptors. In insects, neuropeptides and their receptors play important roles in controlling a multitude of physiological processes. In this project, we sequenced the transcriptome from twelve tissues of the Asian citrus psyllid, Diaphorina citri Kuwayama. A total of 40 candidate neuropeptide genes and 42 neuropeptide receptor genes were identified. Among the neuropeptide receptor genes, 35 of them belong to the A-family (or rhodopsin-like), four of them belong to the B-family (or secretin-like), and three of them are leucine-rich repeat-containing G-protein-coupled receptors. The expression profile of the 82 genes across developmental stages was determined by qRT-PCR. Our study provides the first investigation on the genes of neuropeptides and their receptors in D. citri, which may play key roles in regulating the physiology and behaviors of D. citri.



2005 ◽  
Vol 10 (8) ◽  
pp. 765-779 ◽  
Author(s):  
Wayne R. Leifert ◽  
Amanda L. Aloia ◽  
Olgatina Bucco ◽  
Richard V. Glatz ◽  
Edward J. McMurchie

Signal transduction by G-protein-coupled receptors (GPCRs) underpins a multitude of physiological processes. Ligand recognition by the receptor leads to activation of a genericmolecular switch involving heterotrimeric G-proteins and guanine nucleotides. Signal transduction has been studied extensively with both cell-based systems and assays comprising isolated signaling components. Interest and commercial investment in GPCRs in areas such as drug targets, orphan receptors, highthroughput screening, biosensors, and so on will focus greater attention on assay development to allow for miniaturization, ultra-high throughput and, eventually, microarray/biochip assay formats. Although cell-based assays are adequate for many GPCRs, it is likely that these formatswill limit the development of higher density GPCRassay platforms mandatory for other applications. Stable, robust, cell-free signaling assemblies comprising receptor and appropriate molecular switching components will form the basis of future GPCR assay platforms adaptable for such applications as microarrays. The authors review current cell-free GPCR assay technologies and molecular biological approaches for construction of novel, functional GPCR assays.



2019 ◽  
Vol 87 (4) ◽  
Author(s):  
Alexandra Anderson ◽  
Yee Lian Chew ◽  
William Schafer ◽  
Rachel McMullan

ABSTRACT G protein-coupled receptors contribute to host defense across the animal kingdom, transducing many signals involved in both vertebrate and invertebrate immune responses. While it has become well established that the nematode worm Caenorhabditis elegans triggers innate immune responses following infection with numerous bacterial, fungal, and viral pathogens, the mechanisms by which C. elegans recognizes these pathogens have remained somewhat more elusive. C. elegans G protein-coupled receptors have been implicated in recognizing pathogen-associated damage and activating downstream host immune responses. Here we identify and characterize a novel G protein-coupled receptor required to regulate the C. elegans response to infection with Microbacterium nematophilum. We show that this receptor, which we designate pathogen clearance-defective receptor 1 (PCDR-1), is required for efficient pathogen clearance following infection. PCDR-1 acts upstream of multiple G proteins, including the C. elegans Gαq ortholog, EGL-30, in rectal epithelial cells to promote pathogen clearance via a novel mechanism.





2018 ◽  
Vol 47 (1) ◽  
pp. 377-397 ◽  
Author(s):  
Benjamin Stauch ◽  
Vadim Cherezov

G protein–coupled receptors (GPCRs) represent a large superfamily of membrane proteins that mediate cell signaling and regulate a variety of physiological processes in the human body. Structure-function studies of this superfamily were enabled a decade ago by multiple breakthroughs in technology that included receptor stabilization, crystallization in a membrane environment, and microcrystallography. The recent emergence of X-ray free-electron lasers (XFELs) has further accelerated structural studies of GPCRs and other challenging proteins by overcoming radiation damage and providing access to high-resolution structures and dynamics using micrometer-sized crystals. Here, we summarize key technology advancements and major milestones of GPCR research using XFELs and provide a brief outlook on future developments in the field.





2012 ◽  
Vol 40 (2) ◽  
pp. 383-388 ◽  
Author(s):  
Xavier Deupi ◽  
Jörg Standfuss ◽  
Gebhard Schertler

GPCRs (G-protein-coupled receptors) are seven-transmembrane helix proteins that transduce exogenous and endogenous signals to modulate the activity of downstream effectors inside the cell. Despite the relevance of these proteins in human physiology and pharmaceutical research, we only recently started to understand the structural basis of their activation mechanism. In the period 2008–2011, nine active-like structures of GPCRs were solved. Among them, we have determined the structure of light-activated rhodopsin with all the features of the active metarhodopsin-II, which represents so far the most native-like model of an active GPCR. This structure, together with the structures of other inactive, intermediate and active states of rhodopsin constitutes a unique structural framework on which to understand the conserved aspects of the activation mechanism of GPCRs. This mechanism can be summarized as follows: retinal isomerization triggers a series of local structural changes in the binding site that are amplified into three intramolecular activation pathways through TM (transmembrane helix) 5/TM3, TM6 and TM7/TM2. Sequence analysis strongly suggests that these pathways are conserved in other GPCRs. Differential activation of these pathways by ligands could be translated into the stabilization of different active states of the receptor with specific signalling properties.



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