8bx7

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Structure of the rod CNG channel bound to calmodulin

Structural highlights

8bx7 is a 5 chain structure with sequence from Bos taurus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CNGB1_BOVIN Subunit of cyclic nucleotide-gated (CNG) channels, nonselective cation channels, which play important roles in both visual and olfactory signal transduction. When associated with CNGA1, it is involved in the regulation of ion flow into the rod photoreceptor outer segment (ROS), in response to light-induced alteration of the levels of intracellular cGMP (By similarity).

Publication Abstract from PubMed

Calmodulin (CaM) regulates many ion channels to control calcium entry into cells, and mutations that alter this interaction are linked to fatal diseases. The structural basis of CaM regulation remains largely unexplored. In retinal photoreceptors, CaM binds to the CNGB subunit of cyclic nucleotide-gated (CNG) channels and, thereby, adjusts the channel's Cyclic guanosine monophosphate (cGMP) sensitivity in response to changes in ambient light conditions. Here, we provide the structural characterization for CaM regulation of a CNG channel by using a combination of single-particle cryo-electron microscopy and structural proteomics. CaM connects the CNGA and CNGB subunits, resulting in structural changes both in the cytosolic and transmembrane regions of the channel. Cross-linking and limited proteolysis-coupled mass spectrometry mapped the conformational changes induced by CaM in vitro and in the native membrane. We propose that CaM is a constitutive subunit of the rod channel to ensure high sensitivity in dim light. Our mass spectrometry-based approach is generally relevant for studying the effect of CaM on ion channels in tissues of medical interest, where only minute quantities are available.

Structural basis of calmodulin modulation of the rod cyclic nucleotide-gated channel.,Barret DCA, Schuster D, Rodrigues MJ, Leitner A, Picotti P, Schertler GFX, Kaupp UB, Korkhov VM, Marino J Proc Natl Acad Sci U S A. 2023 Apr 11;120(15):e2300309120. doi: , 10.1073/pnas.2300309120. Epub 2023 Apr 3. PMID:37011209^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Barret DCA, Schuster D, Rodrigues MJ, Leitner A, Picotti P, Schertler GFX, Kaupp UB, Korkhov VM, Marino J. Structural basis of calmodulin modulation of the rod cyclic nucleotide-gated channel. Proc Natl Acad Sci U S A. 2023 Apr 11;120(15):e2300309120. PMID:37011209 doi:10.1073/pnas.2300309120