FK-binding Protein Is Associated with the Ryanodine Receptor of Skeletal Muscle in Vertebrate Animals

Qi, Ying; Ogunbunmi, Eunice M.; Freund, E; Timerman, Anthony P.; Fleischer, Sidney

doi:10.1074/jbc.273.52.34813

Cited by 46 publications

(30 citation statements)

References 28 publications

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“…FKBP12 was labeled with red fluorescent Alexa 555. In the absence of FKBP12.6, SR membranes bound 55.7 Ϯ 5.8 pmol of Alexa 555-FKBP12/mg of protein, consistent with a binding stoichiometry of four FKBP12 per RyR1 tetramer (30). The addition of wild-type, unlabeled FKBP12.6 fully inhibited FKBP12 binding (Fig.…”

Section: Resultsmentioning

confidence: 64%

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: Resultsmentioning

confidence: 64%

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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“…Ethanol significantly enhanced the mean amplitude (A expressed as % ∆F/F) and the mean rate of rise (dA/dt) in both wt RyR3-(P<0.05 and P<0.05, respectively) and V2322D RyR3-expressing HEK293 cells (P<0.001 and P<0.001, respectively) but the effect was much more pronounced in the V2322D RyR3 group. et al , 1992;Timerman et al, 1993;Brillantes et al, 1994;Mayrleitner et al, 1994;Timerman et al, 1994;Lam et al, 1995;Timerman et al, 1996;Qi et al, 1998), whereas the situation for Ins(1,4.5)P3Rs is controversial (Cameron et al, 1995a;Cameron et al, 1995b;Cameron et al, 1997;Shou et al, 1998;Bultynck et al, 2000;Bultynck et al, 2001a;Bultynck et al, 2001b;Carmody et al, 2001;Dargan et al, 2002). The interaction site of FKBP12 with intracellular Ca 2+ -release channels appears to involve a peptidylprolyl residue with the first peptidyl residue always being a hydrophobic amino acid (leucyl, isoleucyl, valyl).…”

Section: Expression Of Wt Ryr3 and V2322d Ryr3 In Hek293 Cells And Imentioning

confidence: 99%

The 12 kDa FK506-binding protein, FKBP12, modulates the Ca2+-flux properties of the type-3 ryanodine receptor

Acker

Bultynck

Rossi

et al. 2004

Journal of Cell Science

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2+ stores is mainly mediated by two distinct families of tetrameric intracellular Ca 2+ -release channels, ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (Ins(1,4.5)P3Rs) (Berridge et al., 2000). Both channels are encoded by three different genes, leading to the expression of three different isoforms. The activity of these channels is tightly regulated by a plethora of cellular factors, such as Ca 2+ , pH, redox state, ATP and associated proteins (Mackrill, 1999;Patel et al., 1999;Bultynck et al., 2003).The type-1 RyR (RyR1) is predominantly expressed in skeletal muscle cells and is physiologically activated upon depolarisation of the plasma membrane by direct interaction with the dihydropyridine receptor. The type-2 RyR (RyR2) is predominantly expressed in cardiac muscle cells and is physiologically activated by Ca 2+ influx through voltagedependent L-type channels. The type-3 RyR (RyR3) is ubiquitously expressed in many cell types at very low levels, with the exception of diaphragm, neurons and skeletal muscle cells. It is physiologically activated by Ca 2+ -induced Ca 2+ release. The Ca 2+ -flux properties of the RyR1 and RyR2 are modulated through association with FK506-binding proteins (FKBPs), which belong to the class of immunophilins . It was shown that the 12 kDa FKBP (FKBP12) strongly associated with RyR1 with a stoichiometry of 4 FKBP12 molecules per tetrameric channel (Jayaraman et al., 1992). FKBP12 was essential for the cooperativity among the four different subunits of the RyR1 channel and for the stabilisation and activation of the channel (Timerman et al., 1993;Brillantes et al., 1994). Furthermore, Marks and coworkers demonstrated that FKBP12 was also involved in

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“…In mammals FKBP12 and 12.6 bind to RyRs with a stoichiometry of four FKBPs per RyR homotetramer (Jayaraman et al 1992;Timerman et al 1993;Qi et al 1998). Under physiological conditions (i.e., the absence of immunosuppressive drugs), FKBPs are though to bind to RyRs with high affinity and stabilize the closed state of the channel (Ahern et al 1994;Brillantes et al 1994;McCall et al 1996;Ahern et al 1997;Marx et al 1998;Marx et al 2001).…”

Section: Calsequestrinmentioning

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

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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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FK-binding Protein Is Associated with the Ryanodine Receptor of Skeletal Muscle in Vertebrate Animals

Cited by 46 publications

References 28 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

The 12 kDa FK506-binding protein, FKBP12, modulates the Ca2+-flux properties of the type-3 ryanodine receptor

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

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