Conserved Protein Domain Family
7tmC_TAS1R

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cd15046: 7tmC_TAS1R 
type 1 taste receptors, member of the class C of seven-transmembrane G protein-coupled receptors
This subfamily represents the type I taste receptors (TAS1Rs) that belongs to the class C family of G protein-coupled receptors. The functional TAS1Rs are obligatory heterodimers built from three known members, TAS1R1-3. TAS1R1 combines with TAS1R3 to form an umami taste receptor, which is responsible for the perception of savory taste, such as the food additive monosodium glutamate (MSG); whereas the combination of TAS1R2-TAS1R3 forms a sweet-taste receptor for sugars and D-amino acids. On the other hand, the type II taste receptors (TAS2Rs), which belong to the class A family of GPCRs, recognize bitter tasting compounds. In the case of sweet, for example, the TAS1R2-TAS1R3 heterodimer activates phospholipase C (PLC) via alpha-gustducin, a heterodimeric G protein that is involved in perception of sweet and bitter tastes. This activation leads to generation of inositol (1, 4, 5)-trisphosphate (IP3) and diacylglycerol (DAG), and consequently increases intracellular Ca2+ mobilization and activates a cation channel, TRPM5. In contrast to the TAS1R2-TAS1R3 heterodimer, TAS1R3 alone could activate adenylate cyclase leading to cAMP formation in the absence of alpha-gustducin. Each TAS1R contains a large extracellular Venus flytrap-like domain in the N-terminus, cysteine-rich domain (CRD) and seven-transmembrane (7TM) domain, which are characteristics of the class C GPCRs. The Venus flytrap-like domain shares strong sequence homology to bacterial periplasmic binding proteins and possess the orthosteric amino acid and calcium binding sites for members of the class C, including CaSR, GABA-B1, GPRC6A, mGlu, and TAS1R receptors.
Statistics
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PSSM-Id: 320174
View PSSM: cd15046
Aligned: 3 rows
Threshold Bit Score: 361.457
Threshold Setting Gi: 123895153
Created: 10-Dec-2013
Updated: 26-Jul-2017
Structure
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Aligned Rows:
  next features
Feature 1:putative allosteric modulator binding site [chemical binding site]
Evidence:
  • Comment:based on the binding of human mGluR1 receptor to a negative allosteric modulator FITM (contacts at 4A)

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                                                 #           ##  ##  #  
gi 116242831 564 APTIAVALLAALGFLSTLAILVIFWRHFQtpiVRSAGGPMCFLMLTLLLVAYMVVPVYVgppkVSTCLCRQALFPLCFTI 643
gi 82261670  571 PMSVALLFFLVCCLLMTSSSAVILLLNINtpvAKSAGGRTCLLMLAALTAAAMSSLCHFgqpsPLACMLKQPLFTFSFTV 650
gi 123895153 550 TAAVVILVGAGLLLALTLAMCVLFAINYNtpvVRSAGGPMCFLILGCLSLCSISIFFFFdkptVAFCVLRFLPFVLFYTV 629
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                                                                       #
gi 116242831 644 CISCIAVRSFQIvcafkmasrfpraysywvryqgPYVSMAFITVLKMVIVVIGMLATGlspttrtdpddpkitivscNPN 723
gi 82261670  651 CLACIAVRSLQVvcifkfasrlppaydrwaknhgPEATIFIASAAILCVSVLRVAVGPpqpsqdldf-ytdsivlecSNT 729
gi 123895153 630 CLACFVVRSFQIvsifkiaakfpqahswwmkyhgQWLVISVTFVIQAFLIIVSLSSDPpspfrdivs--ypdkiilgCFM 707
                        170       180       190       200       210       220       230       240
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1            #  ##  #                                 #  ##  #   #       ##  #  #   #    
gi 116242831 724 YRNSLLFNTSLDLLLSVVGFSFAYMGKELptnYNEAKFITLSMTFYFTSSVSLCTFMSaysGVLVTIVDLLVTVLNLLAI 803
gi 82261670  730 LSPGSFVELCYVSLLSAVCFVFSYMGKDLpanYNEAKCVTFSLMVYMISWISFFTVYLisrGPFTMAAYVCATLVSVLAF 809
gi 123895153 708 NLKTSSGSTVLLLSLGSLCFIFSYMGKDLpknYNEAKAITFCLLLLILTWIIFTTASLlyqGKYIHSLNALAVLSSIYSF 787
                        250
                 ....*....|....
Feature 1                      
gi 116242831 804 SLGYFGPKCYMILF 817
gi 82261670  810 FGGYFLPKIYIIVL 823
gi 123895153 788 LLWYFLPKCYIIIF 801

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