Latrophilins updated

2014 ◽  
Vol 5 (6) ◽  
pp. 457-478 ◽  
Author(s):  
Diana G. Meza-Aguilar ◽  
Antony A. Boucard

AbstractLatrophilins (LPHN) are part of a yet unexplored family of receptors comprising three isoforms, LPHN1-3, and belonging to a unique branch of G protein-coupled receptors (GPCR) named adhesion GPCR (aGPCR). LPHN are considered to be prototypical models for the study of aGPCR as they are one of the most evolutionary conserved members. Previously described as the target for a potent neurotoxin from the black widow spider venom, LPHN are now being studied under a whole new perspective. Indeed, recent advances have provided a better understanding of different aspects of this prototypical family of receptors: 1) elucidation of LPHN ectodomain organization by crystallography has unveiled a new functional domain with great repercussion on all the other members of the aGPCR family, 2) proteomic approaches have opened the gate to unsuspected functional characteristics of LPHN cellular role, and 3) genetic approaches have provided hints into the physiological functions of LPHN in specific systems and organisms. Moreover, genomic linkage studies screening human patients from diverse genetic backgrounds have involved LPHN gene defects in human disorders such as attention-deficit hyperactivity disorder and cancer. In this review, we will provide a historical perspective addressing experimental research on these receptors while highlighting the new advances and discoveries concerning LPHN functions. As GPCR still represent the most studied targets for the development of pharmacological approaches aiming at alleviating human disorders, the relevance of studying LPHN retains a high pertinence to better understand these receptors for the treatment of human diseases.

2013 ◽  
Vol 394 (8) ◽  
pp. 937-950 ◽  
Author(s):  
Ines Liebscher ◽  
Torsten Schöneberg ◽  
Simone Prömel

Abstract Adhesion G protein-coupled receptors (aGPCR) form the second largest class of GPCR. They are phylogenetically old and have been highly conserved during evolution. Mutations in representatives of this class are associated with severe diseases such as Usher Syndrome, a combined congenital deaf-blindness, or bifrontal parietal polymicrogyria. The main characteristics of aGPCR are their enormous size and the complexity of their N termini. They contain a highly conserved GPCR proteolytic site (GPS) and several functional domains that have been implicated in cell-cell and cell-matrix interactions. Adhesion GPCR have been proposed to serve a dual function as adhesion molecules and as classical receptors. However, until recently there was no proof that aGPCR indeed couple to G proteins or even function as classical receptors. In this review, we have summarized and discussed recent evidence that aGPCR present many functional features of classical GPCR, including multiple G protein-coupling abilities, G protein-independent signaling and oligomerization, but also specific signaling properties only found in aGPCR.


2021 ◽  
Vol 22 (16) ◽  
pp. 8678
Author(s):  
Ying Liu ◽  
Xiaoyun Wang ◽  
Danhui Dong ◽  
Luqin Guo ◽  
Xiaonan Dong ◽  
...  

As crucial signal transducers, G-proteins and G-protein-coupled receptors (GPCRs) have attracted increasing attention in the field of signal transduction. Research on G-proteins and GPCRs has mainly focused on animals, while research on plants is relatively rare. The mode of action of G-proteins is quite different from that in animals. The G-protein α (Gα) subunit is the most essential member of the G-protein signal cycle in animals and plants. The G-protein is activated when Gα releases GDP and binds to GTP, and the relationships with the GPCR and the downstream signal are also achieved by Gα coupling. It is important to study the role of Gα in the signaling pathway to explore the regulatory mechanism of G-proteins. The existence of a self-activated Gα in plants makes it unnecessary for the canonical GPCR to activate the G-protein by exchanging GDP with GTP. However, putative GPCRs have been found and proven to play important roles in G-protein signal transduction. The unique mode of action of G-proteins and the function of putative GPCRs in plants suggest that the same definition used in animal research cannot be used to study uncanonical GPCRs in plants. This review focuses on the different functions of the Gα and the mode of action between plants and animals as well as the functions of the uncanonical GPCR. This review employs a new perspective to define uncanonical GPCRs in plants and emphasizes the role of uncanonical GPCRs and Gα subunits in plant stress resistance and agricultural production.


2020 ◽  
Vol 44 (10) ◽  
pp. 2124-2136 ◽  
Author(s):  
Tomáš Suchý ◽  
Christian Zieschang ◽  
Yulia Popkova ◽  
Isabell Kaczmarek ◽  
Juliane Weiner ◽  
...  

Abstract Background G protein-coupled receptors (GPCR) are well-characterized regulators of a plethora of physiological functions among them the modulation of adipogenesis and adipocyte function. The class of Adhesion GPCR (aGPCR) and their role in adipose tissue, however, is poorly studied. With respect to the demand for novel targets in obesity treatment, we present a comprehensive study on the expression and function of this enigmatic GPCR class during adipogenesis and in mature adipocytes. Methods The expression of all aGPCR representatives was determined by reanalyzing RNA-Seq data and by performing qPCR in different mouse and human adipose tissues under low- and high-fat conditions. The impact of aGPCR expression on adipocyte differentiation and lipid accumulation was studied by siRNA-mediated knockdown of all expressed members of this receptor class. The biological characteristics and function of mature adipocytes lacking selected aGPCR were analyzed by mass spectrometry and biochemical methods (lipolysis, glucose uptake, adiponectin secretion). Results More than ten aGPCR are significantly expressed in visceral and subcutaneous adipose tissues and several aGPCR are differentially regulated under high-caloric conditions in human and mouse. Receptor knockdown of six receptors resulted in an impaired adipogenesis indicating their expression is essential for proper adipogenesis. The altered lipid composition was studied in more detail for two representatives, ADGRG2/GPR64 and ADGRG6/GPR126. While GPR126 is mainly involved in adipocyte differentiation, GPR64 has an additional role in mature adipocytes by regulating metabolic processes. Conclusions Adhesion GPCR are significantly involved in qualitative and quantitative adipocyte lipid accumulation and can control lipolysis. Factors driving adipocyte formation and function are governed by signaling pathways induced by aGPCR yielding these receptors potential targets for treating obesity.


2017 ◽  
Vol 149 (2) ◽  
pp. 181-197 ◽  
Author(s):  
Ping Lu ◽  
Cheng-Hai Zhang ◽  
Lawrence M. Lifshitz ◽  
Ronghua ZhuGe

Bitter taste receptors (TAS2Rs or T2Rs) belong to the superfamily of seven-transmembrane G protein–coupled receptors, which are the targets of >50% of drugs currently on the market. Canonically, T2Rs are located in taste buds of the tongue, where they initiate bitter taste perception. However, accumulating evidence indicates that T2Rs are widely expressed throughout the body and mediate diverse nontasting roles through various specialized mechanisms. It has also become apparent that T2Rs and their polymorphisms are associated with human disorders. In this review, we summarize the physiological and pathophysiological roles that extraoral T2Rs play in processes as diverse as innate immunity and reproduction, and the major challenges in this emerging field.


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