4PAS

Heterodimeric coiled-coil structure of human GABA(B) receptor

Summary for 4PAS

• Entry DOI: 10.2210/pdb4pas/pdb
• Descriptor: Gamma-aminobutyric acid type B receptor subunit 1, Gamma-aminobutyric acid type B receptor subunit 2 (3 entities in total)
• Functional Keywords: gaba(b) receptor, coiled-coil, heterodimer, signaling protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 2
• Total formula weight: 9735.72

Authors

Burmakina, S.,Geng, Y.,Chen, Y.,Fan, Q.R. (deposition date: 2014-04-10, release date: 2014-05-07, Last modification date: 2023-12-27)

Primary citation

Burmakina, S.,Geng, Y.,Chen, Y.,Fan, Q.R.
Heterodimeric coiled-coil interactions of human GABAB receptor.
Proc.Natl.Acad.Sci.USA, 111:6958-6963, 2014

PubMed Abstract: Metabotropic GABAB receptor is a G protein-coupled receptor that mediates inhibitory neurotransmission in the CNS. It functions as an obligatory heterodimer of GABAB receptor 1 (GBR1) and GABAB receptor 2 (GBR2) subunits. The association between GBR1 and GBR2 masks an endoplasmic reticulum (ER) retention signal in the cytoplasmic region of GBR1 and facilitates cell surface expression of both subunits. Here, we present, to our knowledge, the first crystal structure of an intracellular coiled-coil heterodimer of human GABAB receptor. We found that polar interactions buried within the hydrophobic core determine the specificity of heterodimer pairing. Disruption of the hydrophobic coiled-coil interface with single mutations in either subunit impairs surface expression of GBR1, confirming that the coiled-coil interaction is required to inactivate the adjacent ER retention signal of GBR1. The coiled-coil assembly buries an internalization motif of GBR1 at the heterodimer interface. The ER retention signal of GBR1 is not part of the core coiled-coil structure, suggesting that it is sterically shielded by GBR2 upon heterodimer formation.

PubMed: 24778228
DOI: 10.1073/pnas.1400081111

Experimental method

X-RAY DIFFRACTION (1.62 Å)