4EQF

Trip8b-1a#206-567 interacting with the carboxy-terminal seven residues of HCN2

Summary for 4EQF

• Entry DOI: 10.2210/pdb4eqf/pdb
• Related: 1FCH 3CVP 3CVQ
• Descriptor: PEX5-related protein, Potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 2 (2 entities in total)
• Functional Keywords: accessory protein, tetratricopeptide repeat, tpr, accessory protein for hcn channels, hcn, protein binding-transport protein complex, protein binding/transport protein
• Biological source: Mus musculus (mouse); More
• Cellular location: Cytoplasm (By similarity): Q8C437; Membrane; Multi-pass membrane protein: O88703
• Total number of polymer chains: 2
• Total formula weight: 41746.79

Authors

Bankston, J.R.,Camp, S.S.,Dimaio, F.,Lewis, A.S.,Chetkovich, D.M.,Zagotta, W.N. (deposition date: 2012-04-18, release date: 2012-05-30, Last modification date: 2023-09-13)

Primary citation

Bankston, J.R.,Camp, S.S.,Dimaio, F.,Lewis, A.S.,Chetkovich, D.M.,Zagotta, W.N.
Structure and stoichiometry of an accessory subunit TRIP8b interaction with hyperpolarization-activated cyclic nucleotide-gated channels.
Proc.Natl.Acad.Sci.USA, 109:7899-7904, 2012

PubMed Abstract: Ion channels operate in intact tissues as part of large macromolecular complexes that can include cytoskeletal proteins, scaffolding proteins, signaling molecules, and a litany of other molecules. The proteins that make up these complexes can influence the trafficking, localization, and biophysical properties of the channel. TRIP8b (tetratricopetide repeat-containing Rab8b-interacting protein) is a recently discovered accessory subunit of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels that contributes to the substantial dendritic localization of HCN channels in many types of neurons. TRIP8b interacts with the carboxyl-terminal region of HCN channels and regulates their cell-surface expression level and cyclic nucleotide dependence. Here we examine the molecular determinants of TRIP8b binding to HCN2 channels. Using a single-molecule fluorescence bleaching method, we found that TRIP8b and HCN2 form an obligate 4:4 complex in intact channels. Fluorescence-detection size-exclusion chromatography and fluorescence anisotropy allowed us to confirm that two different domains in the carboxyl-terminal portion of TRIP8b--the tetratricopepide repeat region and the TRIP8b conserved region--interact with two different regions of the HCN carboxyl-terminal region: the carboxyl-terminal three amino acids (SNL) and the cyclic nucleotide-binding domain, respectively. And finally, using X-ray crystallography, we determined the atomic structure of the tetratricopepide region of TRIP8b in complex with a peptide of the carboxy-terminus of HCN2. Together, these experiments begin to uncover the mechanism for TRIP8b binding and regulation of HCN channels.

PubMed: 22550182
DOI: 10.1073/pnas.1201997109

Experimental method

X-RAY DIFFRACTION (3 Å)