HCAR3 Membrane Protein Introduction

Introduction of HCAR3

HCAR3 (Hydroxycarboxylic acid receptor 3), also known as niacin receptor 2 (NIACR2), GPR109B and GPRHM74, is encoded by HCAR3 gene. It is a G_i/G_o-coupled G protein-coupled receptor which belongs to the hydroxycarboxylic acid family (the other identified member being HCA2). This receptor is predominantly expressed in adipocytes and mediates antilipolytic effects. The ligands of HCAR3 have been identified as 3-hydroxylated b-oxidation intermediates, in particular 3-hydroxy-octanoate. HCAR3 also has low-affinity binding with nicotinic acid (niacin).

Basic Information ofHCAR3
Protein Name	Hydroxycarboxylic acid receptor 3
Gene Name	HCAR3
Aliases	GPR109B, GPRHM74,NIACR2, Nicotinic acid receptor 2
Organism	Homo sapiens (Human)
UniProt ID	P49019
Transmembrane Times	7
Length (aa)	387
Sequence	MNRHHLQDHFLEIDKKNCCVFRDDFIAKVLPPVLGLEFIFGLLGNGLALWIFCFHLKSWKSSRIFLFNLA VADFLLIICLPFVMDYYVRRSDWKFGDIPCRLVLFMFAMNRQGSIIFLTVVAVDRYFRVVHPHHALNKIS NWTAAIISCLLWGITVGLTVHLLKKKLLIQNGTANVCISFSICHTFRWHEAMFLLEFFLPLGIILFCSAR IIWSLRQRQMDRHAKIKRAITFIMVVAIVFVICFLPSVVVRIHIFWLLHTSGTQNCEVYRSVDLAFFITL SFTYMNSMLDPVVYYFSSPSFPNFFSTLINRCLQRKITGEPDNNRSTSVELTGDPNKTRGAPEALIANSG EPWSPSYLGPTSNNHSKKGHCHQEPASLEKQLGCCIE

Function of HCAR3 Membrane Protein

The binding of nicotinic acid to HCAR3 leads to a G-protein-mediated decrease in cAMP levels. 3-OH-octanoic acid has anti-lipolytic activity, and its plasma concentration in humans reflects the β-oxidation flux, and it is a highly specific agonist of HCAR3. Studies have shown that HCAR3 and 3-OH-octanoic acid also mediate a negative feedback regulation of adipocyte lipolysis to offset prolipolytic impacts on the conditions that the β-oxidation rates increase physiologically or pathologically. This pharmacological effect calls for much higher nicotinic acid doses compared with those provided by a normal diet. HCAR3 is shown to inhibit forskolin-induced activation of a cAMP response element through the D isomers of tryptophan, phenylalanine, and kynurenic acid. Given the wide expression of HCAR3 in various immune and inflammatory cells, it will undoubtedly be interesting to investigate the potential of HCAR3 agonists to treat immune disorders of the skin but also of other organs.

Fig.1 Structure of G protein-coupled receptors membrane protein.

Application of HCAR3 Membrane Protein in Literature

Irukayama-Tomobe Y., et al. Aromatic D-amino acids act as chemoattractant factors for human leukocytes through a G protein-coupled receptor, GPR109B. Proceedings of the National Academy of Sciences. 2009, 106(10): 3930-3934. PubMed ID: 19237584

This article suggested that the aromatic D-amino acids, such as D-phenylalanine and D-tryptophan, elicited a chemotactic response in human neutrophils via activation of GPR109B.
Ahmed K., et al. Deorphanization of GPR109B as a receptor for the beta-oxidation intermediate 3-OH-octanoic acid and its role in the regulation of lipolysis. J Biol Chem. 2009, 284(33): 21928-33. PubMed ID: 19561068

The results of this article indicated that the ligand-receptor pair 3-OH-octanoic acid/GPR109B in humans mediated a negative feedback regulation of adipocyte lipolysis to counteract prolipolytic influences under conditions of physiological or pathological increases in beta-oxidation rates.
Knowles H.J., et al. Niacin induces PPARgamma expression and transcriptional activation in macrophages via HM74 and HM74a-mediated induction of prostaglandin synthesis pathways. BiochemPharmacol. 2006, 71(5): 646-56. PubMed ID: 16386710

Authors in this group demonstrated that HM74 and HM74a can mediate macrophage responses to niacin via activation of the prostaglandin synthesis pathway and induction and activation of PPARgamma. This suggested a novel mechanism(s) mediating the clinical effects of pharmacological doses of niacin.
Ahmed K., et al. GPR109A, GPR109B and GPR81, a family of hydroxy-carboxylic acid receptors. Trends Pharmacol Sci. 2009, 30(11): 557-62. PubMed ID: 19837462

This article proposes that the hydroxy-carboxylic acid structure of their endogenous ligands was the defining property of this receptor subfamily and that hydroxy-carboxylic acid receptors functioned as metabolic sensors which fine-tune the regulation of metabolic pathways.

HCAR3 Preparation Options

To obtain the soluble and functional target protein, we present robust reconstitution forms as well as multiple active formats for membrane proteins. Our versatile Magic™ membrane protein production platform enables many flexible options, from which you can always find a better match for your particular project. Aided by our versatile Magic™ anti-membrane protein antibody discovery platform, we also provide customized anti-HCAR3 antibody development services.

The membrane protein service team in creative Biolabs has several years of experience in membrane protein preparation using our efficient and validated strategies. In complement to our regular membrane protein preparation service, we also provide custom services based on the requirements of the clients to meet the specific demand. Please feel free to contact us for more details.

All listed services and products are For Research Use Only. Do Not use in any diagnostic or therapeutic applications.

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