Extracellular calcium-sensing receptor - P41180 (CASR_HUMAN)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for P41180: 4
 
Function
G-protein-coupled receptor that senses changes in the extracellular concentration of calcium ions and plays a key role in maintaining calcium homeostasis (PubMed:7759551, PubMed:8702647, PubMed:8636323, PubMed:8878438, PubMed:17555508, PubMed:19789209, PubMed:21566075, PubMed:22114145, PubMed:23966241, PubMed:25292184, PubMed:25104082, PubMed:26386835, PubMed:25766501, PubMed:22789683). Senses fluctuations in the circulating calcium concentration and modulates the production of parathyroid hormone (PTH) in parathyroid glands (By similarity). The activity of this receptor is mediated by a G-protein that activates a phosphatidylinositol-calcium second messenger system (PubMed:7759551). The G-protein-coupled receptor activity is activated by a co-agonist mechanism: aromatic amino acids, such as Trp or Phe, act concertedly with divalent cations, such as calcium or magnesium, to achieve full receptor activation (PubMed:27434672, PubMed:27386547). UniProt
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Subunit Structure
Homodimer; disulfide-linked (PubMed:27434672, PubMed:27386547, PubMed:16740594). Interacts with VCP and RNF19A (PubMed:16513638). Interacts with ARRB1 (By similarity). UniProt
Domain
The extracellular regions of the homodimer interact in a side-by-side fashion while facing opposite directions (PubMed:27434672, PubMed:27386547). Each extracellular region consists of three domains, LB1 (ligand-binding 1), LB2 and CR (cysteine-rich) (PubMed:17360426). The two lobe-shaped domains LB1 and LB2 form a venus flytrap module (PubMed:27434672, PubMed:27386547). In the inactive configuration, the venus flytrap modules of both protomers are in the open conformation associated with the resting state (open-open) and the interdomain cleft is empty (PubMed:27434672). In addition, each protomer contains three anions, which reinforce the inactive conformation, and one calcium ion (PubMed:27434672). In the active configuration, both protomers of extracellular regions have the closed conformation associated with agonist-binding (closed-closed) (PubMed:27434672, PubMed:27386547). The ligand-binding cleft of each protomer is solely occupied by an aromatic amino-acid (PubMed:27434672, PubMed:27386547). Calcium is bound at four novel sites, including one at the homodimer interface (PubMed:27434672, PubMed:27386547). Agonist-binding induces large conformational changes within the extracellular region homodimer: first, the venus flytrap module of each protomer undergoes domain closure (PubMed:27434672, PubMed:27386547). Second, the LB2 regions of the two protomers approach each other, resulting in an expansion of the homodimer interactions involving LB2 domains (PubMed:27434672, PubMed:27386547). Third, the CR regions of the two subunits interact to form a large homodimer interface that is unique to the active state (PubMed:27434672, PubMed:27386547). The CR regions are brought into close contact by the motion involving LB2 since the two domains are rigidly associated within each subunit (PubMed:27434672, PubMed:27386547). UniProt
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Data in green originates from UniProtKB  
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Data in yellow originates from Pfam  , by interacting with the HMMER3 web site  
Data in purple originates from Phosphosite  .
Data in orange originates from the SCOP   (version 1.75) and SCOPe   (version 2.04) classifications.
Data in grey has been calculated using BioJava  . Protein disorder predictions are based on JRONN (Troshin, P. and Barton, G. J. unpublished), a Java implementation of RONN  
  • Red: potentially disorderd region
  • Blue: probably ordered region.
Hydropathy has been calculated using a sliding window of 15 residues and summing up scores from standard hydrophobicity tables.
  • Red: hydrophobic
  • Blue: hydrophilic.
Data in lilac represent the genomic exon structure projected onto the UniProt sequence.
Data in blue originates from PDB
  • Secstruc: Secondary structure projected from representative PDB entries onto the UniProt sequence.
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The PDB to UniProt mapping is based on the data provided by the EBI SIFTS project. See also Velankar et al., Nucleic Acids Research 33, D262-265 (2005).
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