Structural Characterization of the RyR1–FKBP12 Interaction

Samsó, Montserrat; Shen, Xiaohua; Allen, Paul D.

doi:10.1016/j.jmb.2005.12.023

Cited by 93 publications

(82 citation statements)

References 65 publications

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“…Our results provide the first FRET-based distance measurements within the cardiac RyR2 and demonstrate that distance relationships within the RyR1 and RyR2 isoforms are remarkably similar. Results are in excellent agreement with the mode of FKBP12-RyR1 binding predicted by previous cryo-EM studies (21).…”

Section: The 23-mda Ryanodine Receptor (Ryr)supporting

confidence: 89%

“…Cryoelectron microscopy (cryo-EM) and single-particle three-dimensional reconstruction of RyRs in the absence and presence of FKBP12/12.6 have demonstrated that the FKBPs bind within a pocket formed by the intersection of domains 3 and 9 of the RyR1 and RyR2 cytoplasmic assemblies (19,20). More recently, Samsó et al (21) advanced this approach to higher resolution and were able to dock the atomic structure of FKBP12 into the three-dimensional difference map of FKBP12 in a unique orientation. These results suggested a distinct mode of binding, in which the surface formed by the ␤-sheet and adjacent loops of FKBP12 forms a major binding interface with domain 9 of the RyR1 channel, and the hydrophobic drug-binding pocket of FKBP12 faces RyR1 domain 3.…”

Section: The 23-mda Ryanodine Receptor (Ryr)mentioning

confidence: 99%

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Mapping the Ryanodine Receptor FK506-binding Protein Subunit Using Fluorescence Resonance Energy Transfer

Cornea

Nitu

Samsó

et al. 2010

Journal of Biological Chemistry

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Our results show that FKBP12.6 binds to RyR1 and RyR2 in the same orientation and suggest new insights into the discrete structural domains responsible for channel binding and inhibition. FRET mapping of RyR-bound FKBP12.6 is consistent with the predictions of a previous cryoelectron microscopy study and strongly supports the proposed structural model. The 2.3-MDa ryanodine receptor (RyR)2 /Ca 2ϩ release channel isoforms expressed in skeletal muscle (RyR1) and cardiac muscle (RyR2) function in complex with smaller regulatory proteins, which include FK506-binding proteins (FKBP12 and FKBP12.6) and calmodulin (CaM) (1, 2). The FKBPs tightly bind to RyR channels and may function to stabilize channels in a fully closed conformational state while minimizing the occurrence of subconductance states (3, 4).Disruption of FKBP binding to RyRs has been proposed to underlie increased channel openings in response to ␤-adrenergic stimulation (5), oxidation/nitrosylation (6 -8), or diseasecausing channel mutations (9 -11), and the FKBP binding interface is now under investigation as a therapeutic target for disordered Ca 2ϩ regulation in cardiac and skeletal muscle. However, the fundamental cellular and molecular mechanisms that govern FKBP binding remain poorly defined, and the significance of reduced FKBP binding in RyR channelopathies is controversial (12-16). Because no atomic structure of an FKBP⅐RyR complex is currently available, uncertainty regarding the specific structural domains that comprise the binding interface remains a significant gap in understanding.Molecular determinants of FKBP binding have been investigated previously through mutagenesis of FKBP12 and FKBP12.6 (17,18). However, the key determinants thus far identified are broadly distributed throughout the FKBP threedimensional structure and do not provide a clear indication of a major RyR binding interface. Cryoelectron microscopy (cryo-EM) and single-particle three-dimensional reconstruction of RyRs in the absence and presence of FKBP12/12.6 have demonstrated that the FKBPs bind within a pocket formed by the intersection of domains 3 and 9 of the RyR1 and RyR2 cytoplasmic assemblies (19,20). More recently, Samsó et al. (21) advanced this approach to higher resolution and were able to dock the atomic structure of FKBP12 into the three-dimensional difference map of FKBP12 in a unique orientation. These results suggested a distinct mode of binding, in which the surface formed by the ␤-sheet and adjacent loops of FKBP12 forms a major binding interface with domain 9 of the RyR1 channel, and the hydrophobic drug-binding pocket of FKBP12 faces RyR1 domain 3.Here, we extend an approach (22) based on site-directed labeling of channel regulatory proteins and fluorescence resonance energy transfer (FRET) to further investigate the structural basis of FKBP binding to RyR channels. We identify structural determinants of both high affinity binding and RyR inhibition. We define the orientation of FKBP12.6 when bound to both the RyR1 and the RyR2 channel isoforms. Ou...

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Section: The 23-mda Ryanodine Receptor (Ryr)supporting

confidence: 89%

Section: The 23-mda Ryanodine Receptor (Ryr)mentioning

confidence: 99%

Mapping the Ryanodine Receptor FK506-binding Protein Subunit Using Fluorescence Resonance Energy Transfer

Cornea

Nitu

Samsó

et al. 2010

Journal of Biological Chemistry

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“…The amino-terminal and the carboxy-terminal regions of RyR2 have also been suggested to interact with FKBP12.6 Xiao et al 2004;Zissimopoulos and Lai 2005). Difference mapping of threedimensional reconstructions of RyR with and without FKBP12 or 12.6 places the FKBPs binding site between subdomains 3, 5, and 9 (Wagenknecht et al 1996;Wagenknecht et al 1997;Samsó et al 2006;Sharma et al 2006). In agreement with this localization, FRET studies have localized the FKBP12 (Cornea et al 2009) and the FKBP12.6 (Cornea et al 2010) binding site to the same area as the model from Samsó et al 2006.…”

Section: Calsequestrinmentioning

confidence: 61%

“…The clamps (Fig. 3, subdomains 5, 6, 7, 8, 9, 10) undergo major conformational changes during the opening and closing of the channel (Serysheva et al 2008;Samsó et al 2009), are likely to participate in intermolecular interactions with neighboring RyRs, and are the sites of interactions with modulators Wagenknecht et al 1996;Wagenknecht et al 1997;Samsó and Wagenknecht 2002;Samsó et al 2006;Sharma et al 2006;Meng et al 2009). Two of the areas of high divergence in the primary sequence of the RyR isoforms were mapped in the clamps Liu et al 2004).…”

Section: Structural Studies On Ryrsmentioning

confidence: 99%

Ryanodine Receptors: Structure, Expression, Molecular Details, and Function in Calcium Release

Lanner¹,

Georgiou²,

Joshi³

et al. 2010

Cold Spring Harbor Perspectives in Biology

658

572

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Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca 2þ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle. RyRs are the largest known ion channels (.2MDa) and exist as three mammalian isoforms (RyR 1 -3), all of which are homotetrameric proteins that interact with and are regulated by phosphorylation, redox modifications, and a variety of small proteins and ions. Most RyR channel modulators interact with the large cytoplasmic domain whereas the carboxy-terminal portion of the protein forms the ion-conducting pore. Mutations in RyR2 are associated with human disorders such as catecholaminergic polymorphic ventricular tachycardia whereas mutations in RyR1 underlie diseases such as central core disease and malignant hyperthermia. This chapter examines the current concepts of the structure, function and regulation of RyRs and assesses the current state of understanding of their roles in associated disorders.

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“…Putative surface-exposed mutation residues are labeled. The basin between subregions 3, 5, and 9 (indicated with dashed line) is proposed to form the FKBP-12 binding site in RyR1 (31,32) and is identified to include four surface-exposed MH/CCD mutation sites (E161, R164, R402, and I404). The surface of the adjacent RyR1 subunit is shown with a mesh.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Subnanometer-resolution electron cryomicroscopy-based domain models for the cytoplasmic region of skeletal muscle RyR channel

Serysheva¹,

Ludtke²,

Baker³

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

104

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The skeletal muscle Ca 2؉ release channel (RyR1), a homotetramer, regulates the release of Ca 2؉ from the sarcoplasmic reticulum to initiate muscle contraction. In this work, we have delineated the RyR1 monomer boundaries in a subnanometer-resolution electron cryomicroscopy (cryo-EM) density map. In the cytoplasmic region of each RyR1 monomer, 36 ␣-helices and 7 ␤-sheets can be resolved. A ␤-sheet was also identified close to the membranespanning region that resembles the cytoplasmic pore structures of inward rectifier K ؉ channels. Three structural folds, generated for amino acids 12-565 using comparative modeling and cryo-EM density fitting, localize close to regions implicated in communication with the voltage sensor in the transverse tubules. Eleven of the 15 disease-related residues for these domains are mapped to the surface of these models. Four disease-related residues are found in a basin at the interfaces of these regions, creating a pocket in which the immunophilin FKBP12 can fit. Taken together, these results provide a structural context for both channel gating and the consequences of certain malignant hyperthermia and central core disease-associated mutations in RyR1.Ca 2ϩ release channels ͉ cryo-EM ͉ 3D Structure ͉ modeling

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Structural Characterization of the RyR1–FKBP12 Interaction

Cited by 93 publications

References 65 publications

Mapping the Ryanodine Receptor FK506-binding Protein Subunit Using Fluorescence Resonance Energy Transfer

Mapping the Ryanodine Receptor FK506-binding Protein Subunit Using Fluorescence Resonance Energy Transfer

Ryanodine Receptors: Structure, Expression, Molecular Details, and Function in Calcium Release

Subnanometer-resolution electron cryomicroscopy-based domain models for the cytoplasmic region of skeletal muscle RyR channel

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