Investigations of the contribution of a putative glycine hinge to ryanodine receptor channel gating

Euden, Joanne ORCID: https://orcid.org/0000-0002-2844-6878, Mason, Sammy, Viero, Cedric, Thomas, Nia Lowri ORCID: https://orcid.org/0000-0001-8822-8576 and Williams, Alan John 2013. Investigations of the contribution of a putative glycine hinge to ryanodine receptor channel gating. Journal of Biological Chemistry 288 (23) , pp. 16671-16679. 10.1074/jbc.M113.465310

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Abstract

Ryanodine receptor channels (RyR) are key components of striated muscle excitation-contraction coupling, and alterations in their function underlie both inherited and acquired disease. A full understanding of the disease process will require a detailed knowledge of the mechanisms and structures involved in RyR function. Unfortunately, high-resolution structural data, such as exist for K+-selective channels, are not available for RyR. In the absence of these data, we have used modeling to identify similarities in the structural elements of K+ channel pore-forming regions and postulated equivalent regions of RyR. This has identified a sequence of residues in the cytosolic cavity-lining transmembrane helix of RyR (G4864LIIDA4869 in RyR2) analogous to the glycine hinge motif present in many K+ channels. Gating in these K+ channels can be disrupted by substitution of residues for the hinge glycine. We investigated the involvement of glycine 4864 in RyR2 gating by monitoring properties of recombinant human RyR2 channels in which this glycine is replaced by residues that alter gating in K+ channels. Our data demonstrate that introducing alanine at position 4864 produces no significant change in RyR2 function. In contrast, function is altered when glycine 4864 is replaced by either valine or proline, the former preventing channel opening and the latter modifying both ion translocation and gating. Our studies reveal novel information on the structural basis of RyR gating, identifying both similarities with, and differences from, K+ channels. Glycine 4864 is not absolutely required for channel gating, but some flexibility at this point in the cavity-lining transmembrane helix is necessary for normal RyR function.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Medicine
Subjects:	Q Science > QD Chemistry Q Science > QH Natural history > QH301 Biology
Uncontrolled Keywords:	Calcium Channels; Calcium Intracellular Release; Ion Channels; Ryanodine Receptor; Sarcoplasmic Reticulum (SR); Glycine Hinge; Single Channel Gating
Publisher:	American Society for Biochemistry and Molecular Biology
ISSN:	0021-9258
Date of First Compliant Deposit:	30 March 2016
Last Modified:	11 Jun 2023 11:11
URI:	https://orca.cardiff.ac.uk/id/eprint/49362

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