On Sunday, April 20th 2025, starting 8:30am GMT, there will be maintenance work that will involve the website being unavailable during parts of the day. We apologize for any inconvenience this may cause and appreciate your understanding.
We noted you are experiencing viewing problems
-
Check with your IT department that JWPlatform, JWPlayer and Amazon AWS & CloudFront are not being blocked by your network. The relevant domains are *.jwplatform.com, *.jwpsrv.com, *.jwpcdn.com, jwpltx.com, jwpsrv.a.ssl.fastly.net, *.amazonaws.com and *.cloudfront.net. The relevant ports are 80 and 443.
-
Check the following talk links to see which ones work correctly:
Auto Mode
HTTP Progressive Download Send us your results from the above test links at access@hstalks.com and we will contact you with further advice on troubleshooting your viewing problems. -
No luck yet? More tips for troubleshooting viewing issues
-
Contact HST Support access@hstalks.com
-
Please review our troubleshooting guide for tips and advice on resolving your viewing problems.
-
For additional help, please don't hesitate to contact HST support access@hstalks.com
We hope you have enjoyed this limited-length demo
This is a limited length demo talk; you may
login or
review methods of
obtaining more access.
Printable Handouts
Navigable Slide Index
- Introduction
- Class C G-Protein Coupled Receptors
- Questions
- Human GABAB receptor
- GABAB receptor
- GABABR functions as an obligatory heterodimer
- GBR1:GBR2 ecodomain heterodimer structures
- Apo structure
- Antagonist-bound structures
- Agonist-bound structures
- Heterodimer interactions: resting & active states
- Agonist-binding induced conformational changes
- Ligand binding site
- Chemical structures of agonists and antagonists
- Antagonist-binding site: GBR1:GBR2 complex
- Contacts between GBR1 & different antagonists
- Contacts between GBR1 & different agonists
- Ligand-binding site of the GBR1:GBR2 complex
- Agonist vs. Antagonist binding (1)
- Agonist vs. Antagonist binding (2)
- LB1 mutations in the ligand-binding site
- LB2 mutations in the ligand-binding site
- Implications for receptor activation
- GBR2 closure not needed for receptor activation
- Disulfide-lined GABABR heterodimer: Design
- Disulfide-lined GABABR heterodimer: Formation
- Interfacrial disulfide locks GABABR in active state
- Conformational equilibrium of GABAB receptor
- Human calcium-sensing receptor
- Extracellular calcium-sensing receptor
- Diverse function of calcium-sensing receptor
- Crystallization of deglycosylated CaSR
- CaSR extracellular domain: Inactive structure
- CaSR extracellular domain: Active structure
- Homodimer Interactions: Inactive & Active States
- L-amino acid recognition
- L-amino acids are orthosteric agonists of CaSR
- Common agonist-binding mode: Class C GPCRs
- CaSR-mediated intracellular Ca2+ mobilization
- Amino acids increase CaSR sensitivity to Ca2+
- L-amino acid binding is required for CaSR activity
- Ca2+ -binding sites
- Identification of Ca2+-binding sites in CaSR
- Ca2+ maintains the structural integrity of CaSR
- Ca2+ stabilizes the active conformation of CaSR
- L-amino Acids and Ca2+ are co-agonists of CaSR
- Endogenous agonist of CaSR
- Anion binding sites
- Identification of anion-binding sites in CaSR
- PO43- maintains the structural integrity of CaSR
- PO43- negative modulatory effect: CaSR activity
- Agonist-binding induced conformation changes
- Activation of CaSR: An intricate interplay
- Activation mechanism of class C GPCRs
- Common activation mechanism of class C GPCRs
- Acknowledgements
Topics Covered
- Crystal structures of human GABA(B) receptor extracellular domain in multiple functional states
- Agonist vs. antagonist recognition
- Identification of novel heterodimer interface associated with receptor activation
- Crystal structures of human CaSR in the inactive and active conformations
- Discovery of L-amino acids as orthosteric agonists of CaSR
- Identification of Ca2+ and PO43 binding sites in CaSR
- Universal activation mechanism of class C GPCRs
Links
Series:
Categories:
Talk Citation
Fan, Q.R. (2019, July 31). Extracellular domain structures from calcium-sensing and GABA(B) receptors [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved April 15, 2025, from https://doi.org/10.69645/RERY7138.Export Citation (RIS)
Publication History
- Published on July 31, 2019
Financial Disclosures
- Dr. Qing R. Fan has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
Other Talks in the Series: G Protein-Coupled Receptors (GPCRs) Signaling in Health and Disease
Transcript
Please wait while the transcript is being prepared...
0:00
My name is Qing Fan.
I'm from Colombia University.
The research in my lab involves
the structural studies of class C G-protein coupled receptors.
0:12
GPCRs are divided into different classes
based on the sequence homology of their trans-membrane domains.
Most GPCRs such as rhodopsin and Beta-2 adrenergic receptor belong to class A.
These receptors contain a seven helix trans-membrane domain and can function as monomers.
The ligand binding site of
the class A receptors is located within the trans-membrane domain.
Landmark studies led by Dr. Kodaka's group revealed that agonist binding directly
induces conformational changes among the trans-membrane helices for receptor activation.
Class C GPCRs mediate a number of
key biological phenomena including excitatory and inhibitory neurotransmission,
calcium homeostasis, and taste.
Unlike the class A receptors,
the class GPCRs are characterized by a large extracellular domain.
In addition to the canonical seven helix trans-membrane domain,
this extracellular domain is 500-600 amino
acids long and contains the orthosteric ligand binding site.
Another unique feature of
the class C receptors is that they require dimerization for function.
While metabotropic glutamate receptors and calcium sensing
receptor function as disulfide-linked homodimers,
GABA B receptor and taste receptors are obligatory heterodimers.
Our goal is to use structural methods to probe
the signal transduction mechanisms of class C receptors and GPCR dimers in general.
Specifically, we're focusing on human GABA B receptor and human calcium sensing receptor.
Hide