Structural Basis for Gating and Activation of RyR1

Abstract

Summary The type-1 ryanodine receptor (RyR1) is an intracellular calcium (Ca2+) release channel required for skeletal muscle contraction. Here we present cryo-EM reconstructions of RyR1 in multiple functional states revealing the structural basis of channel gating and ligand-dependent activation. Binding sites for the channel activators Ca2+, ATP and caffeine were identified at interdomain interfaces of the C-terminal domain. Either ATP or Ca2+ alone induce conformational changes in the cytoplasmic assembly (‘priming’), without pore dilation. In contrast, in the presence of all three activating ligands, high-resolution reconstructions of open and closed states of RyR1 were obtained from the same sample, enabling analyses of conformational changes associated with gating. Gating involves global conformational changes in the cytosolic assembly accompanied by local changes in the transmembrane domain, which include bending of the S6 transmembrane segment and consequent pore dilation, displacement and deformation of the S4-S5 linker, and conformational changes in the pseudo-voltage-sensor domain.

Physiology and pathophysiology of excitation–contraction coupling: the functional role of ryanodine receptor

“…RyRs are highly regulated for precise control and Ca 2+ plays the key signaling role in activating the channel and amplifying the signal (Endo et al 1970). In this process, depolarization of the plasma membrane activates L-type voltage-gated calcium channels (Ca v ), which signal RyRs located on the SR to gate open and release Ca 2+ to activate muscle contraction (Rios and Brum 1987; Gordon et al 2000; Tobacman 1996; des Georges et al 2016). RyR is a 2.2 mega Dalton homotetramer, composed of four ~5000 residue protomers (Marks et al 1989; Santulli and Marks 2015), making it the largest kfown ion channel (des Georges et al 2016; Santulli and Marks 2015; Zalk et al 2015).…”

“…In this process, depolarization of the plasma membrane activates L-type voltage-gated calcium channels (Ca v ), which signal RyRs located on the SR to gate open and release Ca 2+ to activate muscle contraction (Rios and Brum 1987; Gordon et al 2000; Tobacman 1996; des Georges et al 2016). RyR is a 2.2 mega Dalton homotetramer, composed of four ~5000 residue protomers (Marks et al 1989; Santulli and Marks 2015), making it the largest kfown ion channel (des Georges et al 2016; Santulli and Marks 2015; Zalk et al 2015). The narrow transmembrane core and larger cytoplasmic shell result in a mushroom shaped structure (des Georges et al 2016; Zalk et al 2015; Hwang et al 2012).…”

Reduced threshold for store overload-induced Ca2+ release is a common defect of RyR1 mutations associated with malignant hyperthermia and central core disease

“…The 3D structure of two RyR monomers [62,64,65] is shown. RyR1 mutations associated with MH and CCD are largely clustered in three hotspot regions: MH/CCD mutation hotspot I (highlighted in yellow), MH/CCD mutation hotspot II (in green), and MH/CCD mutation hotspot III (in cyan).…”

Single‐Particle Reconstruction of Biological Molecules—Story in a Sample (Nobel Lecture)

“…[74] Working with this toolset, multiple structures are now routinely recovered from asingle sample. [77][78][79][80][81] Again resorting to the ribosome to make ageneral point, I…”

“…tions with the groups of Andrew Marks,W ayne Hendrickson, Alexander Sobolevsky,a nd Filippo Mancia demonstrate the gain in knowledge achievable now for membrane-bound channels and receptors (Figure 24 b,c). [80,[94][95][96][97][98] …”