GPR21 Membrane Protein Introduction

Introduction of GPR21

GPR21 is encoded by the GPR21 gene. According to its sequence, it belongs to the G protein-coupled receptor family, which is the largest protein superfamily in the genome. GPR21 is one of a class A orphan GPCRs which has a similar structure to other identified GPCRs and its endogenous ligand has not yet been identified. Meanwhile, GPR21 shares about 71% amino acid identity to GPR52. GPR21 is identified and cloned along with GPR22, GPR23, and GPR20.

Basic Information of GPR21
Protein Name Probable G-protein coupled receptor 21
Gene Name GPR21
Aliases NA
Organism Homo sapiens (Human)
UniProt ID Q99679
Transmembrane Times 7
Length (aa) 349

Function of GPR21 Membrane Protein

GPR21 plays an important role in the migration of macrophages into inflammatory tissue in obesity. The deletion of GPR21 improves the obesity-induced inflammation and the insulin sensitivity and overexpression of GPR21 in vitro can increase the insulin sensitivity. Pharmacological GPR21 inhibition can increase energy expenditure and improve insulin sensitivity to protect against the negative effects of high-fat diet in mice model. GPR21 can activate the mitogen activated protein kinases (MAPKs) signaling pathway and its effect can be reduced in the presence of serum, indicating the possibility of a natural ligand of GPR21. The activation of the MAPKs induced by GPR21 may contribute to the development of type 2 diabetes. GPR21 offers a potential anti-diabetic pharmacological strategy. A molecule identified by homology modeling and ligand docking studies blocks the constitutive activity of GPR21 in a competitive manner to the prospective native ligand could be a novel and powerful pharmacological strategy for the treatment of type 2 diabetes.

Proposed role for GPR21 in the development of type 2 diabetes. Fig.1 Proposed role for GPR21 in the development of type 2 diabetes. (Leonard, 2016)

Application of GPR21 Membrane Protein in Literature

  1. Leonard S., et al. Regulating the effects of GPR21, a novel target for type 2 diabetes. Scientific Reports. 2016, 6: 27002. PubMed ID: 27243589

    This article reports that GPR21 has an important role in the development of obesity-associated type 2 diabetes. A novel compound inhabiting the GPR21 activity offers a potential anti-diabetic pharmacological strategy.

  2. Wang J., et al. GPR21 KO mice demonstrate no resistance to high fat diet induced obesity or improved glucose tolerance. F1000Research. 2016, 5, 136-142. PubMed ID: 27081476

    Authors in this group generate new GPR21 knockout mice using TALENS technology and point out that GPR21 may play an important role in regulating body weight and glucose metabolism in mice model.

  3. Osborn O., et al. G protein-coupled receptor 21 deletion improves insulin sensitivity in diet-induced obese mice. The Journal of Clinical Investigation. 2012, 122, 2444-2453. PubMed ID: 22653059

    The article reveals that GPR21 plays a critical role in coordinating of macrophage proinflammatory activity in obesity and the pharmacological GPR21 inhibition could improve the obesity-induced insulin sensitivity.

  4. Kumar A., et al. Therapeutic molecules against type 2 diabetes: What we have and what are we expecting? Pharmacological Reports. 2017, 69, 959-970. PubMed ID: 28822958

    This article reviews the approved drugs for type 2 diabetes treatment and proposes the novel therapies, such as GPR21 inhibitors and GK activators could be anticipated as safer and more effective approaches for type 2 diabetes treatment.

  5. Gardner J., et al. G-protein-coupled receptor GPR21 knockout mice display improved glucose tolerance and increased insulin response. Biochem Biophys Res Commun. 2012, 418, 1-5. PubMed ID: 22155242

    This article suggests that GPR21 deficient mice are resistant to diet-induced obesity and the findings of this paper indicate that GPR21 may have a vital role in regulating glucose metabolism and body weight in mice model.

GPR21 Preparation Options

To obtain the soluble and functional target protein, the versatile Magic™ membrane protein production platform in Creative Biolabs 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-GPR21 antibody development services.

Creative Biolabs is engaged in the membrane proteins for many years with a good reputation as a leading customer service provider and a forward-looking research institute. We have accomplished various challenging projects related to the functional membrane proteins. Please feel free to contact us for more detailed information.


  1. Leonard S., et al. (2016). Regulating the effects of GPR21, a novel target for type 2 diabetes. Scientific Reports. 6, 27002.

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